The restriction enzymes that cut the bacteriophage DNA cannot cut the bacterial chromosomal DNA.

A. The bacteria can cut the viral DNA at its specific restriction site, but they cannot cut their own DNA since bacterial chromosomal DNA has altogether a different DNA sequence than the viral DNA
B. The bacteria can cut the viral DNA at its specific restriction site but protect their own chromosomal DNA by modifying its bases and blocking the restriction enzyme
C. The bacteria can cut the viral DNA at its specific restriction site but protect their own chromosomal DNA bymodifying the restrict

Question

The restriction enzymes that cut the bacteriophage DNA cannot cut the bacterial chromosomal DNA.

A. The bacteria can cut the viral DNA at its specific restriction site, but they cannot cut their own DNA since bacterial chromosomal DNA has altogether a different DNA sequence than the viral DNA
B. The bacteria can cut the viral DNA at its specific restriction site but protect their own chromosomal DNA by modifying its bases and blocking the restriction enzyme
C. The bacteria can cut the viral DNA at its specific restriction site but protect their own chromosomal DNA bymodifying the restrict

anonymous · Answer

I think the choice is not complete. But the answer is that restriction enzymes (RE) are named like that because its property to restrictly cut sequences. One bacterial  RE which  will not cut (restric-foreign (e.g. viral) DNA that enters the cell, by destroying it.) its own bacterial DNA. Restriction enzymes are found in many different strains of bacteria where their biological role is to participate in cell defense. The host cell has a restriction-modification system that methylates its own DNA at sites specific for its respective restriction enzymes, thereby protecting it from cleavage. Over 800 known enzymes have been discovered that recognize over 100 different nucleotide sequences.