[QA] Gunpowder, in some ways the most effective of all the explosive materials, were a mixture of potassium nitrate, charcoal, and sulfur.

III. Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions

Question:

Gunpowder, in some ways the most effective of all the explosive materials, were a mixture of potassium nitrate, charcoal, and sulfur.

• A.
  in some ways
• B.
  the most effective
• C.
  all
• D.
  were