Answer:
C. The pool contains 18,500 gallons of water before it is drained.
Explanation:
The table shows the amount of water left in a pool, in gallons, over time, in hours, as it is being drained.
Time (h) Water (gal)
0 18,500
1 17,000
2 15,500
3 14,000
This table represents a linear function.
The initial value of the table is,

As here, time is 0 hours i.e at starting of the experiment, the water in the tank was 18,500 gallons.
Therefore, the initial value represents the amount of water before it is drained.