$\"\"$

\

The functions are $\"\"$ and $\"\"$ .

\

Find $\"\"$ .

\

$\"\"$ (Substitute $\"\"$ )

\

$\"\"$ (Simplify)

\

$\"\"$ (Substitute $\"\"$ )

\

$\"\"$ (Multiply)

\

$\"\"$ (Simplify)

\

$\"\"$ .

\

$\"\"$

\

Option C is right choice.