Answer the following question, with explanation first.
What has a nervous system?\nOptions:\n- (A) Nerve tonic\n- (B) Jellyfish\n- (C) Air\n- (D) fur seals\n- (E) Cardiovascular system\n- (F) animals\n- (G) chickens\n- (H) elephants

(B)
Most invertebrates have a nervous system.

Jellyfish and insects are invertebrates.

Jellyfish have a nervous system.

.

The final answer: (B)