A decoder

a$.$ converts $N$ inputs to a $1$ on one of $(2^{**}(N))$ outputs

b$.$ passes one of multiple data inputs to a single output based on control input values

c$.$ converts $N$ inputs to a $1$ on one of $2^N$ outputs

d$.$ converts $N$ inputs to $0$ on one of $(2^{**}(N))$ outputs