PT 40 S1 Q25

Unquestionably, inventors of useful devices deserve credit for their ingenuity, ... ...

The claim that inventors sometimes serve as their own engineers plays which one of the following roles in the argument?
(A) It separates the practical and theoretical aspects of the argument.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: "Method/Function" Questions, Set 3 - Mix (25Q)