Let f(x)=tanx, and let f(n)(x) denote the nth derivative of f. Which of the following statements about f(n)(0) is correct for all positive integers n?
a) f(n)(0)=0 when n is even and f(n)(0)=0 when n is odd.
b) f(n)(0)=0 when n is odd and f(n)(0)=0 when n is even.
c) f(n)(0)=0 only when n is a multiple of 4.},{
d) f(n)(0)=0 for every positive integer n.}