A Particular Solution of the Differential Equation $y ^ { \prime \prime } - 2 y ^ { \prime } + y = \cos x$

Multiple Choice

A particular solution of the differential equation $y ^ { \prime \prime } - 2 y ^ { \prime } + y = \cos x$ is

A) $y _ { p } = \cos x$
B) $y _ { p } = \sin x$
C) $y _ { p } = \sin x / 2$
D) $y _ {p } = \cos x / 2$
E) $y _ { p } = - \sin x / 2$