Which expression is equivalent to 3.5x + 4.8?

(A.) 3 • 0.5x + 4 • 0.8

(B.) 3x • 0.5x + 4 • 0.8

(C.) 3 + 0.5x + 4 + 0.8

(D.) 3x + 0.5x + 4 + 0.8​