Which sentence does not contain any errors in comma usage?
A.In a pool or at a beach, lifeguards are often on duty.
B.In a pool or at a beach lifeguards are often on duty.
C.In a pool, or, at a beach, lifeguards are often on duty.
D.In a pool, or at a beach, lifeguards are often on duty.



Answer :

n a pool or at a beach, lifeguards are often on duty.
D not contain any errors. D is the answer.