Answer
a). Since both conventional currents are to the left, they add to create a net current to the left, so the answer is (2).
b). Current due to protons = $\frac{8.3C}{4.5s}=1.8A$ to the left,
c). Current due to electrons = $\frac{6.7C}{4.5s}=1.5A$ to the left,
d). Total current = $1.8+1.5=3.3A$ to the left.
Work Step by Step
a). Since both conventional currents are to the left, they add to create a net current to the left, so the answer is (2).
b). Current due to protons = $\frac{8.3C}{4.5s}=1.8A$ to the left,
c). Current due to electrons = $\frac{6.7C}{4.5s}=1.5A$ to the left,
d). Total current = $1.8+1.5=3.3A$ to the left.