Choose the appropriate preposition for the given sentence:
The professor has been absent ______ Monday.

কাল বা সময়ের অবস্থান বিন্দু বা মুহূর্ত (point of time) নির্দেশকারী word বা phrase গুলোর পূর্বে ‘since’ preposition টি বসে।
যেমন, since morning, since yesterday, since sunday, since 2000, since Eid day.
Hence, the correct answer is option 2.
Complete Sentence: The professor has been absent since Monday.