From the differential equation of the family of curves $y = A \sin 2x + B \cos 2x$

Question

$(A)\; \frac{d^2y}{dx^2} - 4y =0$
$(B)\; \frac{d^2y}{dx^2} - 2y =0$
$(C)\; \frac{d^2y}{dx^2} + 4y =0$
$(D)\; \frac{d^2y}{dx^2} + 2y =0$