Consider the conditional statement,
if p, then q
Here, p is the hypothesis and q is the conclusion
To write the inverse statement, we would negate both the hypotesis and conclusion. Thus, the inverse statement for p and q is
if not p, then not q
The given statement is
p = if you are in the band then
q = you are not in the chorus
The inverse statement would be
if you are not in the band, then you are in the chorus
The first option is correct