PT 54 S1 Q9

Passage A      Drilling fluids, including the various mixtures known ... ...

Which one of the following can be most reasonably inferred from the two passages taken together, but not from either one individually?
(A) Barite is the largest ingredient of drilling muds, by weight, and also the most environmentally damaging.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: Comparative Reading