The nucleus of atom X is shown using the notation below. $^P_Q X$ How many protons are present in this nucleus, and how many neutrons does it contain?
- Anumber of protons: $P$, number of neutrons: $Q$
- Bnumber of protons: $P$, number of neutrons: $Q - P$
- Cnumber of protons: $Q$, number of neutrons: $P$
- Dnumber of protons: $Q$, number of neutrons: $P - Q$