What is the benefit of cutting the vector and insert with the same restriction enzyme?

Correct answer: Compatible ends can form

The governing principle is complementary end formation during recombinant-DNA construction. If the vector and the DNA insert are cut with the same restriction enzyme, the enzyme usually generates matching sticky ends, or compatible termini, on both molecules. Their exposed single-stranded bases can pair by hydrogen bonding, aligning the insert with the vector so DNA ligase can seal the remaining phosphodiester breaks. Option D is correct. The treatment does not guarantee degradation, produce RNA, or directly produce protein. Protein expression occurs later only if the inserted gene is correctly placed and expressed in a suitable host.