Which of the following details foreshadows a climactic ending?
a. a tidy little cottage of white boards, trimmed vividly with green blinds."
b. "for a moment the progress of the engine could be marked by heavy bellowing puffs of smoke. . "
c. "every day for more than twenty years . . a woman had appeared. . "
d. "he felt for them . . such tenderness as a man might feel for his own children. . "