If 40 $\times$ 10¹⁸ Electrons and 1 $\times$ 10¹⁸ Protons Move in Opposite Directions Past a Given Cross

Multiple Choice

If 4.0 $\times$ 10¹⁸ electrons and 1.5 $\times$ 10¹⁸ protons move in opposite directions past a given cross section of a hydrogen discharge tube every second,the average current in the tube is

A) 0.40 A
B) 0.56 A
C) 0.88 A
D) 1.5 A
E) 4.0 A