The correct option is
A θ=tan−1(12) to the x-axis
There is no external force acting on the spheres. So linear momentum will be conserved.Before the collision, In direction x, Linear momentum =m2v ....1
In direction y, Linear momentum=0
After the collision, spheres moves as shown in figure. Let velocity of sphere A is v1
In direction x, Linear momentum =m1v1cos(θ) ...2
In direction y, Linear momentum =m2v2−m1v1sin(θ) .......3
Linear momentum will be conserved,
From equation 1 and 2, ⇒m1v1cos(θ)=m2v ...4
From the equation 2, ⇒m2v2−m1v1sin(θ)=0 ⇒m1v1sin(θ)=m2v2 ......5
Dividing equation 5 by 4, ⇒tan(θ)=12 ⇒θ=tan−1(12)