Where Do Restriction Enzymes Come From, and What Is Their $\lambda$

Multiple Choice

Where do restriction enzymes come from, and what is their normal physiological function?

A) Phage $\lambda$ produces them and they replicate viral DNA.
B) Phage $\lambda$ produces them and they confer antibiotic resistance.
C) They are yeast DNA replication enzymes.
D) Bacteria produce them to protect against viral invasion.
E) They are bacterial DNA replication enzymes.