Which of the following are the basic elements in a 555 timer IC? (a) Two comparators (b) A flip-flop (c) A discharge transistor (d) A resistive voltage divider

A) (a), (b) and (d)
B) only (a), (b) and (c)
C) only (b), (c) and (d)
D) only (a), (b), (c) and (d)