Aron flips a penny 9 times. Which expression represents the probability of getting exactly 3 heads?

P (k successes) = Subscript n Baseline C Subscript k Baseline p Superscript k Baseline (1 minus p) Superscript n minus k. Subscript n Baseline C Subscript k Baseline = StartFraction n factorial Over (n minus k) factorial times k factorial EndFraction
Subscript 9 Baseline C Subscript 3 Baseline (0.5) cubed (0.5) Superscript 6
Subscript 9 Baseline C Subscript 3 Baseline (0.5) cubed
Subscript 9 Baseline C Subscript 3 Baseline (0.5) cubed (0.5) Superscript 9
Subscript 9 Baseline C Subscript 6 Baseline (0.5) Superscript 6