Which of the Following Is the General Solution of the Homogeneous

Multiple Choice

Which of the following is the general solution of the homogeneous second-order differential equation
are arbitrary real constants.

A) $y=C\left(\cos \frac{t}{3}+\sin \frac{t}{3}\right)$
B) $y=C_{1} \cos (3 t) +C_{2} \sin (3 t)$
C) $y=C(\cos (3 t) +\sin (3 t) )$
D) $y=C_{1} \cos \left(\frac{t}{3}\right) +C_{2} \sin \left(\frac{t}{3}\right)$
E) $y=\cos \left(\frac{t}{3}\right) +\sin \left(\frac{t}{3}\right) +C t$
F) $y=\cos (3 t) +\sin (3 t) +C$