Which of the following will correctly calculate the average of the elements included in the nums array?

Which of the following will correctly calculate the average of the elements included in the nums array?a) while (x < 4){nums[x] = total + total;x += 1;} //end whileavg = static_cast<double>(total) / static_cast<double>(x);b) while (x < 4){total += nums[x];x += 1;} //end whileavg = static_cast<double>(total) / static_cast<double>(x);c) while (x < 4){total += nums[x];x += 1;} //end whileavg = static_cast<double>(total) / static_cast<double>(x)-1;d) while (x < 4){total += nums[x];x += 1;} //end whileavg = static_cast<double>(total) / static_cast<double>(x-1);