18. A uranium nucleus at rest decays into a thorium nucleus and a helium nucleus: ²³⁸U → ²³⁴Th + ⁴He. Which of the following is true?
(A) Each decay product has the same speed.
(B) Each decay product has the same kinetic energy.
(C) The decay products tend to go in the same direction.
(D) The thorium nucleus has more momentum than the helium nucleus.
(E) The helium nucleus has more kinetic energy than the thorium nucleus.