Which statement about brackets is true?
i. brackets often come in threes or fives.
ii. brackets can indicate a change in verb tense.
iii. the phrase [sic] indicates an error in a quoted excerpt.
a. ii only
b. ii and iii
c. i and iii
d. i, ii, and iii

The answer to your question would be that the statements that are true about brackets are the following ones: "Brackets can indicate a change in verb tense" and "the phrase [sic] indicates an error in a quoted excerpt". That is, the correct option would be B, II and III.

You should use brackets to indicate a change in verb tense. With respect to the phrase [sic], it can be used as an adverb to denote that something is quoted as is, including mistakes. If you want to quote something and realize that the source material contains a spelling or grammatical error, you should use sic right after the mistake.  

lol ma dude okay

what’s the difference between santa and jews