Read the following passage and answer the question that follows.

the strange case of dr. jekyll and mr. hyde
by robert louis stevenson
part 1

mr. utterson the lawyer was a man of a rugged countenance, that was never lighted by a smile; cold, scanty and embarrassed in discourse; backward in sentiment; lean, long, dusty, dreary, and yet somehow lovable. at friendly meetings, and when the wine was to his taste, something eminently human beaconed from his eye; something indeed which never found its way into his talk, but which spoke not only in these silent symbols of the after-dinner face, but more often and loudly in the acts of his life. he was austere with himself; drank gin when he was alone, to mortify a taste for vintages; and though he enjoyed the theatre, had not crossed the doors of one for twenty years. but he had an approved tolerance for others; sometimes wondering, almost with envy, at the high pressure of spirits involved in their misdeeds; and in any extremity inclined to rather than to reprove.
"i incline to, cain's heresy*," he used to say. "i let my brother go to the devil in his quaintly 'own way.'" in this character, it was frequently his fortune to be the last reputable acquaintance and the last good influence in the lives of down-going men. and to such as these, so long as they came about his chambers, he never marked a shade of change in his demeanour.
no doubt the feat was easy to mr. utterson; for he was undemonstrative at the best, and even his friendship seemed to be founded in a similar catholicity of good-nature. it is the mark of a modest man to accept his friendly circle ready-made from the hands of opportunity; and that was the lawyer's way. his friends were those of his own blood or those whom he had known the longest; his affections, like ivy, were the growth of time, they implied no aptness in the object. hence, no doubt, the bond that united him to mr. richard enfield, his distant kinsman, the well-known man about town. it was a nut to crack for many, what these two could see in each other, or what subject they could find in common. it was reported by those who encountered them in their sunday walks, that they said nothing, looked singularly dull, and would hail with obvious relief the appearance of a friend. for all that, the two men put the greatest store by these excursions, counted them the chief jewel of each week, and not only set aside occasions of pleasure, but even resisted the calls of business, that they might enjoy them uninterrupted.
*the biblical story of cain and abel is a story about two brothers who gave offerings to god. abel’s offering was accepted by god, but cain’s was not. jealous, cain killed his brother. when god asked cain where abel was, cain said, “am i my brother’s keeper? ” by saying this, cain implied that what his brother did was his own business. (genesis 4: 1-16)

the author uses the phrase "chief jewel" to do which of the following?
demonstrate the wealth these men have
contrast the two different characters
provide a vivid image of jealousy
establish the importance of the walks