What $is$ the difference between a budget projection and a budget estimate?

Question $2$ options:

There $isno$ difference.

A budget estimate $is$ more concrete whereas a budget projection $is$ based $on$ projected revenue, which are unknown.

A budget estimate $is$ provided $at$ the beginning $of$ the year whereas a budget projection $is$ used when reviewing $a5-$year plan $of$ future projections.

A budget projection $is$ more concrete whereas a budget estimate $is$ based $on$ projected revenue, which are unknown.