A bird leaves the branch of a tree and flies in a straight line. The height of the bird can be represented by the linear model b=23+8t, where b is the height of the bird in feet and t is the number of seconds since the bird left the branch. Part A
What is the meaning of the 23 in the linear model?

A. When the bird left the branch, its height was 23 feet.

B. The bird's vertical rate of change is 23 feet per second.

C. The bird's horizontal rate of change is 23 feet per second.

D. Eight seconds after the bird left the branch, its height was 23 feet.