The correct option is A 4
We know, third side rule of triangle states that, third side of a triangle is less than the other two sides of triangle,
Here in triangle ABC, let AC be the third side, AB and BC be the other two sides.
Let AB and BC be x, as AB=BC
As per rule,
7<x+x
⇒7<2x
⇒x>3.5
Since x>3.5, smallest possible value of x will be 4.