Answer: b. Lin buys a pack of 87 pencils. She gives 39 to her teacher and shared the remaining pencils between herself and 3 friends.
Explanation:
Lin buys 87 pencils which is why the entire number line adds up to 87.
She gave 39 of these pencils to her teacher which s why there is a section of the number line that is unlike the rest and is 39 in number.
The rest of the number line is a set of 4 spaces which are equal.
Lin shared the remaining pencils between herself and 3 friends which means she shared the pencils with 4 people. These four equal quantities of pencils are the 4 spaces.