Let $f, g$ and h be continuous functions on [$0, a$] such that $f\left(x\right)=f(a-x),g\left(x\right)=-g(a-x)$ and $3h\left(x\right)-4h(a-x)=5\text{. Then }{\int }_0^a f\left(x\right)g\left(x\right)h\left(x\right)\mathrm{d}x$

is equal to

• A

  5/4

• B

  3/4

• C

  1

• D

  none of these