Triangle def has been dilated to form triangle d'e'f'. what is the least amount of information needed to determine if the two triangles are similar?
a) angle f=f', angle e=e', and segments ec and e'c' are congruent.
b) segment ec=e'c', segment df=d'f', and angles e and e' are congruent.
c) angles e and e' are congruent, and angles f and f' are congruent.
d) segments df and d'f' are congruent, and segments ef and e'f' are congruent.