The Immune System Can Be Said to Have a "Memory

Multiple Choice

The immune system can be said to have a "memory" because:

A) the location of the immune system in the brain is close to the hippocampus.
B) once it encounters an antigen,the immune system will recognize it in the future.
C) the location of the immune system in the brain is close to the hypothalamus.
D) the immune system and the memory areas of the brain develop at the same time.