To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) totquantity = sum(totquantity + quantity);
- This option is incorrect because the
sum function is unnecessary in this context. The sum function is typically used to calculate the sum of multiple variables, but here we only need to add the quantity to the existing value of totquantity.
Option B) totquantity + quantity;
- This option is correct because it adds the quantity to the existing value of totquantity. By using the "+" operator, the value of totquantity will be updated correctly.
Option C) totquantity 0; sum totquantity;
- This option is incorrect because it has a syntax error. It seems that the code is trying to assign a value of 0 to totquantity, but the correct syntax should be "totquantity = 0;" instead of "totquantity 0;". Additionally, the "sum" statement is unnecessary in this context.
Option D) retain totquantity 0; totquantity = totquantity + quantity;
- This option is incorrect because it uses the
retain statement, which is not necessary in this case. The retain statement is used to retain the value of a variable across iterations of the data step, but here we don't need to retain the value of totquantity.
The correct answer is B) totquantity + quantity. This option is correct because it adds the quantity to the existing value of totquantity, producing the desired result.