Astudent is attempting to simplify the express below. sample mathematical work is shows. which statement best applies to the sample mathematical work?

given a+b-2(ab-a), i first apply the distributive property, which yields the expression a+b-2ab+2a. i can then collect like terms: since a+2a=3a, i have the expression 3a+b-2ab as my final answer

a) the student failed to properly apply the distributive property
b) the student collected two or more terms that were not like terms
c) the student failed to collect all like terms
d) the mathematical work shown above is correct