সঠিক উত্তর:  of which.

• Complete sentence: The scouts in my school were sure to visit the flooded town, the condition of which was not known.

• Explanation:
- এই বাক্যটিতে "the flooded town" (বন্যাপীড়িত শহর) এবং "the condition" (অবস্থা) এর মধ্যে সম্পর্ক বোঝাতে একটি সঠিক Relative Pronoun প্রয়োজন।
- The phrase "the condition of which" means "the condition of the flooded town."
- এখানে "the flooded town" হলো antecedent (পূর্বপদ).
- "the condition of which was not known" = "the condition of the flooded town was not known".

• Given options:
- in which → ভুল (এটি স্থান নির্দেশ করে, যেমন- "the house in which he lives", কিন্তু এখানে শহরের অবস্থা বোঝাতে "in" অপ্রাসঙ্গিক)।

- whose → ভুল ("whose" is used for possession by people or personified things, যেমন- "the man whose car was stolen")।
- "whose" -এর পরে সাধারণত noun বসে।

- that → ভুল ("that" is not suitable for non-defining clauses like this)।
- "that" সাধারণত people, animals and things, ইত্যাদি ক্ষেত্রে defining clause -এ informally ব্যবহৃত হয়।
- যেমন- The 8.30 is the train that you need to get. (refers to a thing)

ঘ) of which → সঠিক (এটি Formal English-এ ব্যবহৃত হয় এবং "the condition of the town" বোঝায়)।
- "Of which" is a relative phrase that introduces a subordinate clause, providing additional information about a previously mentioned noun.

• More examples:
- "They visited the village, the beauty of which was amazing."
- (এখানে "the beauty of which" = "the beauty of the village").