Part A:
Part B: 6 feet above sea level and positive
Step-by-step explanation:
The elevation of city A is 60 feet above sea level.
The elevation of city C is 12 feet above sea level.
The elevation of city D is of the elevation of city C.
Part A: Expression which shows Elevation of city D in feet above sea level.
Part B: Simplify the expression of part A
The elevation of city D is 6 feet above sea level.
It would be positive because above sea level height is positive and below sea level takes negative.
