What potential difference between the two plates would be needed to accelerate a hydrogen ion (a proton) from rest to a speed of $10^6 \mathrm{~m} / \mathrm{s}$ ?
(A) $100 \mathrm{~V}$
(B) $500 \mathrm{~V}$
(C) $1000 \mathrm{~V}$
(D) $5000 \mathrm{~V}$
(E) $10,000 \mathrm{~V}$