The figure above shows a portion of the graph of the function f. If f(x+5) = f(x) for all values of x, then f(x) = 0 for how many different values of x between 0 and 12?

http://img187.imageshack.us/img187/4666/dsc00054i.jpg

a. 8

b. 9

c. 10

d. 11

e. 12

thanks

also whats a period graph of function? hows it related to the question?

thanks