Which of the Following Best Describes the Relationship Between the Atoms

Multiple Choice

Which of the following best describes the relationship between the atoms described below?
$\begin{array} { l l } \text { Atom 1 } & \text { Atom 2 } \\{ } _ { 15 } ^ { 13 } \mathrm { P } & { } _ { 15 } ^ { 33 } \mathrm { P }\end{array}$

A) They contain 31 and 32 electrons, respectively.
B) They are both phosphorus cations.
C) They are both phosphorus anions.
D) They are both isotopes of phosphorus.
E) They contain 31 and 32 protons, respectively.