The algebraic expression of the statement "Four-fifth of x multiplied by the difference of a and b" (Assume that a is less than b) ?

Question

( A ) \large\frac{4}{5}  x(b/a)
( B ) \large\frac{4}{5}  (b - xa)
( C ) \large\frac{4}{5}  x(b - a)
( D ) \large\frac{4}{5}  (xb - a)