Answer:
Option). the uneven cutting by most restriction enzymes
Explanation:
Sticky ends can be defined as over-hanged DNA fragments of unequal length, having a terminal portion with unpaired nucleotides. These fragments are formed by a staggered cut on DNA molecules wit the help of restriction endonuclease enzymes.
These ends have complementary nucleotide bases that allow complementary base pairing between bases, and thus, known as sticky ends.
Thus, the correct answer is 'last option.'