Why are there more tissues available for transplant than organs?

A) Tissues can be transplanted regardless of blood type, but the blood types must match between organ donors and recipients.
B) Nonhuman animals are the source of most tissue transplants, but organs for transplant must come from humans.
C) Tissues can be removed from living donors, whereas organs can only be removed from dead bodies.
D) Tissues can be frozen and preserved, but organs deteriorate quickly without nourishment from oxygen and blood.