If I call the following function with n = 10

How many times does fibo get call which n = 4 

a. 0

b. 6

c. 1

d. 13

e. 7 

f. Can't be determine. 

def fibo(n): if n == 1 or n=- 2: return 1 else: return fibo(n-2) + fibo(n-1)