Answer:
B

Explanation:
In order to get the same denominator, we need to multiply the second fraction by (b+2) in the numerator and denominator.
We will end up in something like this :

I just timed the second fraction by b+ 2 and then i added them together.
Therefore, we will get

now factoring the numerator we will end like this

we will then end up with the answer.
Hope this helps.