PT 19 S4 Q22

When a planetary system forms, the chances that a planet capable of supporting ... ...

Knowing which one of the following would be most useful in evaluating the argument?
(A) whether all planetary systems are formed from similar amounts of matter
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: "Weaker" Questions, Set 2 - "Evaluation" Subset