Deductions from the Given Information

The most important deduction is that the given information can be separated into two extreme scenarios, one in which we make the distances between the power station and substations as bunched together as possible and one in which we separate them as much as possible.

In the first extreme case, we try to minimize the distance of each substation from the power station. In the latter case, we assume that two of the substations are a distance of $9$ and a third a distance of $14$ from the power station, which is allowed because all three substations are still within the square region.

Solving the Problem

Basically, all of the work for this problem was done in the deductions step of the process. In extreme case 1, the sum of the distances from the power station to each of the substations is clearly less than Quantity B -- $30$ -- and in the other case, the sum equals $9 + 9 + 14=32$, which is larger than Quantity B.

Thus, the answer is D, It cannot be determined.