A

Step 1: Understand the charge of the α particle. An α particle consists of 2 protons and 2 neutrons, thus its charge (q) is +2e, where e is the elementary charge, approximately 1.6 x 10^-19 C. Therefore, q = 2 × 1.6 x 10^-19 C = 3.2 x 10^-19 C.

Step 2: Use the formula for potential energy (U) in an electric field, which is given by:
U = qV, where V is the electric potential.

Step 3: Substitute the values into the equation:
U = (3.2 x 10^-19 C)(5 V) = 1.6 x 10^-18 J.

Step 4: Therefore, the potential energy of the α particle is 1.6 x 10^-18 J.