Code flow can be tricky to follow. What is the function call sequence $($excluding returns$)$ and the output for the following program:

def delta$($num$)$:

if num $>1$:

num $=$ num $-2$

else:

num $=$ num $+2$

return num

def gamma$($num$)$:

if num $>1$:

num $=$ num $/2$

else:

num $=$ num $/-2$

return num

def beta$($num$)$:

if num $>1$:

num $=$ num $*2$

num $=$ gamma$($num$)$

else:

num $=$ num $*-2$

num $=$ delta$($num$)$

return num

def alpha$($num$)$:

if num $>0$:

num $+=1$

num $=$ beta$($gamma$($num$))$

else:

num $-=1$

num $=$ beta$($delta$($num$))$

return num

print$(\text{'}$output $=\text{'},$ alpha$(0))$

a$.)$

alpha, delta, beta, delta with an output of output $=0$

b$.)$

alpha, delta, beta, delta with an output of output $=3$

c$.)$

alpha, delta, beta, delta with an output of output $=6$

d$.)$

alpha, gamma, beta, gamma with an output of output $=0$