Respuesta :
A; you have to add the grades to have the total and then divide by 3 because there are 3 variables.Â
Answer:
Option B (grade1 + grade2 + grade3) / 3.0
Explanation:
The most accurate result is calculated by the expression given in the option B. Â This is because all the grade1, grade2 and grade3 variables are integer type and therefore we need to add a decimal point after divisor (e.g. 3.0) so that the decimal points of the result can be preserved.
For example:
(88 + 92 + 83) / 3.0 Â should result in 87.66666666666667
If we do  (88 + 92 + 83) / 3, the decimal points are truncated to 87.
The expression in option c, (double)((grade1 + grade2 + grade3) / 3), will result in 87 as the  (grade1 + grade2 + grade3) / 3 will be evaluated first prior to converting into double type.
The expression in option d and e are inaccurate as they don't calculate average of the three variables. Â