6. Given this function: int sum_nums (int total, pair p) { return total + (p.first * p.second); what is the value of the variable named sum after the following code is executed? multimap nums{ {2, 10}, {3, 20}, {3, 30}, {4, 40} }; int sum = accumulate(nums.begin(), nums.end(), 0, sum_nums); a. 100 b. 200 c. 330 d. 1200