Answer:
Option (4).
Explanation:
If a function is f(x) = 7x - 3
Inverse of the function will be,
g(x) =
=

Now composite function f[g(x)] =

= x
And g[f(x)] =

= x
Hence, condition for the inverse functions will be,
f[g(x)] = g[f(x)] = x
Therefore, Option (4) will describe the the composition of two functions.