Final answer:
The total power produced by all 15 generators in the hydroelectric grid is 450 GW, calculated by multiplying 30 GW per generator by 15.
Step-by-step explanation:
To calculate the total power produced by all 15 generators in the hydroelectric grid, you simply multiply the power output of one generator by the number of generators. Each generator produces 30 GW of power. Multiply 30 GW by 15 to find the total power output.
30 GW/generator × 15 generators = 450 GW
Therefore, the correct answer is (a) 450 GW.