Only P : to make himself Q : by shouting at the top of his voice R : was he able S : heard The Proper sequence should be:

The correct answer is A. PSQR.

Here is a brief explanation of each option:

• Option A: PSQR. This is the correct answer because it is the only option that puts the words in the correct order. The sentence should read “Only by shouting at the top of his voice was he able to make himself heard.”
• Option B: PSRQ. This option is incorrect because it puts the word “only” after the word “himself.” The word “only” should come before the word “himself” in order to make the sentence grammatically correct.
• Option C: QPRS. This option is incorrect because it puts the word “was” after the word “he.” The word “was” should come before the word “he” in order to make the sentence grammatically correct.
• Option D: QRPS. This option is incorrect because it puts the word “heard” after the word “himself.” The word “heard” should come before the word “himself” in order to make the sentence grammatically correct.