Choose the correct replacement of the given sentence :
Here is a pool which we can swim in !

The correct answer is Option C (Here is a pool to swim in !).

Key Points:
• This question evaluates the candidate's understanding of Infinitives and prepositional endings, a crucial grammatical concept frequently tested in MPSC and other competitive examinations. Grasping the correct structural replacement is essential for sentence improvement.
• Option 3 is the correct answer according to the official MPSC answer key. The phrase 'to swim in' correctly uses the infinitive form ('to' + base verb) while retaining the necessary preposition 'in' to indicate the location of the action.
• Let us analyze why the other options are grammatically flawed. Option 1 is incorrect because 'for swim' is grammatically invalid; it should be 'for swimming', but even then, it lacks idiomatic correctness here. Option 2 mixes the infinitive marker 'to' with the gerund 'swimming', creating an invalid structure. Option 4 'swimming in' functions poorly as an adjectival modifier without proper relative markers.
• A common MPSC trap for students is dropping the preposition at the end of such infinitive phrases, which leaves the verb's relationship to the noun incomplete.
• Consistent practice of sentence transformation rules ensures higher accuracy and prevents unnecessary loss of marks.
• Key Takeaway: Remember: When using an infinitive to modify a noun, you must include the preposition if the verb requires one (e.g., a chair to sit on, a pool to swim in).