Answer:
Option B. 4
Explanation:
The given expression is x² + 4x + -----
We have to find a number which can be added in the expression to make it a perfect square trinomial.
x² + 2(2x) + 2²
= (x + 2)²
Therefore, if we add 4 in the given expression it becomes a perfect trinomial.
Option B is the correct option.