Step 1: Understanding the structure “No sooner… than”.
The structure “No sooner + auxiliary verb + subject + verb + than” is used to show that one action happens immediately after another.
In the given sentence, both verbs are in the present tense: “does enter” and “gets”.
So, we must rewrite it using the correct equivalent structure of “as soon as” while maintaining the same tense.
Step 2: Applying the rule of “As soon as”.
“As soon as” is used to express immediate succession of two actions.
When the main clause is in the simple present tense, the clause with “as soon as” should also be in the simple present tense.
Therefore, the correct structure will be:
“As soon as + subject + simple present verb, subject + simple present verb.”
Step 3: Analyzing the options.
(A) uses past perfect “had entered” with present “gets” — tense mismatch, incorrect.
(B) uses incorrect verb form “have entered” with singular subject — grammatically incorrect.
(C) uses correct simple present tense “enters” and “gets” — grammatically correct and matches the meaning.
(D) uses “will enter” — future tense is incorrect after “as soon as” in time clauses.
Step 4: Conclusion.
The correct rewriting using “as soon as” while maintaining proper tense and grammar is option (C).