The answer is: [A]: parentheses .
______________________________________________________
The mnemonic to remember is:
__________________________________________________________
PE MD AS ; or:
BE MD AS
_______________________________
Please excuse my dear Aunt Sally/Susan. ; or:
Be excused, my dear Aunt Sally/Susan.
____________________________________
which means, start with Parentheses (or BRACKETS);
THEN do exponents;
Then "multiplication division" (from left to right as they appear);
Then "addition subtraction" (from left to right, as they appear).
_____________________________________________
The three (3) answer choices given are:
_____________________________
a) parentheses ;
b) exponents;
c) multiplication division.
____________________________
We know from our mnemonic that BOTH parentheses AND exponents (i.e. choices "A" and "B" come before "Multiplication and Division" (answer choice "C"); so we can rule out "answer choice C". We are left with answer choices: a) parentheses; and: b) exponents. We know from our mnemonic that parentheses come before exponents, so, we rule out "answer choice B", and we know that "answer choice: {A}: parentheses" — is the correct answer.
______________________________________________