Which of the following best describes a balanced tree?

Question $2$ Select one:

a$.$

A balanced tree has all leaves at exactly the same level.

b$.$

A balanced tree has no leaves at exactly the same level.

c$.$

A balanced tree has half of the leaves at one level and half the leaves at another level.

d$.$

A balanced tree has all of the leaves within one level of each other.

e$.$

None of the above correctly describes a balanced tree.