Which of the following statements about min-heaps is true?

a. Smaller values are on the left and larger values are on the right.

b. The smallest value is the root.

c. The smallest value is one of the leaves.

d. Every value is smaller than all values at lower levels of the tree. For example, if there is a 25 at level 3, there will not be any elements with values less than 25 at levels 4 and beyond.

e. The peek operation returns the largest value in the heap.