Which lines in this excerpt from act v of romeo and juliet show that romeo feels guilty about having killed juliet’s cousin tybalt?

a) mercutio's kinsman, noble county paris!
what said my man, when my betossed soul
did not attend him as we rode? i think
he told me paris should have married juliet:

b) how oft when men are at the point of death
have they been merry! which their keepers call
a lightning before death: o, how may i
call this a lightning? o my love! my wife!

c) o, what more favour can i do to thee,
than with that hand that cut thy youth in twain
to sunder his that was thine enemy?
forgive me, cousin! ah, dear juliet,

d) from this world-wearied flesh. eyes, look your last!
arms, take your last embrace! and, lips, o you
the doors of breath, seal with a righteous kiss
a dateless bargain to engrossing death!