The correct answer is A. Before beginning your project, make sure you purchase all the items you will need: colored pencils, drawing paper, and a ruler.
Explanation:
In grammar, there are multiple punctuation marks including the period (.), the comma (;), the colon (:), etc. and each of them is used with different purposes and in different situations. In the case of the comma, this punctuation mark is used to separate elements in a list and other sections of the sentence including introductory phrases or phrases that add non-essential information. On the other hand, in the case of colon(:) these are mainly used to introduce a list of items.
This means in the case of the sentence presented it is necessary to place a comma after "Before beginning your project" because this is an introductory phrase and also commas should be used to separate the items of the list "colored pencils drawing paper and a ruler". Besides this, a semicolon should be included before the first item or "color pencils" to introduce the list. Thus, the sentence that is punctuated correctly is "Before beginning your project, make sure you purchase all the items you will need: colored pencils, drawing paper, and a ruler".
