Can someone help me with biology home work?

The complementary overhangs of restriction enzymes form a 'scar' between the Promoter and Chromoprotein. This scar cannot be digested by any of the four restriction enzymes used to create BioBricks. This allows for iterative building of more complex BioBricks. Why can the scar not be cut, despite retaining the overhang sequence?

Select one:

a. Because the scar is not a palindrome.

b. Because the scar has a distorted double helix that cannot be recognized by the restriction enzyme.

c. Because restriction enzymes only cut at one sequence of DNA.

d. Because restriction enzymes recognize additional DNA sequence beyond the overhang region