The sentence is grammatically correct as written. Often, the word "does" can be moved to the position it is found in choice (B); in this case, that is confusing. Because the item being compared contains the word "and," moving the word "does" to this earlier position raises the possibility that "a commonly used" and "a more expensive dietary supplement" are two separate items. This confusion is not present if "does" follows the item being compared.

The mistake in (B) reappears in (E), eliminating that choice. (C) is wrong due to the word "will," which is the future tense, while "halts" is present tense. (D) is inefficient and inelegant; the construction "at the halting of" is needlessly long compared to the simpler "halts" used in the first three choices. (A) is correct.