Which of phrases given below each sentence should replace the phrase quotation marks to make the grammatically correct? If the sentence is correct as it is, mark 'D' as the answer.They "should have calmly thought of" the advantages that would accrue to them.

• A. should have been calm in thinking about
• B. should be calmly thought of
• C. shall have to calmly thought of
• D. No correction required