What is the time complexity of the below algorithm:

def myFunction$($n$)$:

if n $<2$:

out $=1$

else:

out $=$ myFunction$($n$-1)+$ myFunction$($n$-2)$

return out

Group of answer choices

O$(2^$n$)$

O$($log$($n$))$

O$($n log$($n$))$

O$($n$^2)$