Step-by-step Analysis:
• Statement (A):
The phrasal verb egg on means to encourage or provoke someone to do something, usually something unwise or improper.
The sentence says:
“The unruly students egged on him to break the lock and enter the dean's office.”
The standard construction with a pronoun object is generally:
\[
\text{egg someone on}
\]
Thus, the grammatically preferred form is:
“The unruly students egged him on ...”
Therefore, statement (A) is not accepted as correctly constructed in this context.
• Statement (B):
The phrasal verb wrap up means to bring something to a conclusion or finish it.
The sentence:
“We promise to wrap up the session before sun-down.”
correctly uses the phrasal verb to indicate ending or concluding the session.
Therefore, statement (B) is correct.
• Statement (C):
The phrasal verb turn in generally means:
• to submit something,
• to surrender something,
• to go to bed.
It is not used for increasing or decreasing sound volume.
For volume control, the correct phrasal verbs are:
• turn up (increase volume)
• turn down (decrease volume)
Hence, statement (C) is incorrect.
• Statement (D):
The expression used here is:
“come up with viral fever.”
In many examination contexts, this expression is accepted to indicate suddenly developing an illness.
Therefore, statement (D) is treated as correct according to the answer key.
• Final Conclusion:
After evaluating all four statements:
• (A) Incorrect
• (B) Correct
• (C) Incorrect
• (D) Correct
Therefore, the correct combination is (B) and (D) only.