Given:
Bella bought packs of stickers to give to her friends.
Cost of each pack of stickers = $4
Total amount spent on packs of stickers = $12
To find:
The equation for the given statement.
Solution:
Let s be the number of packs of stickers.
Cost of one pack of stickers = $4
Cost of s packs of stickers = $4s
Total amount spent on packs of stickers is $12. So,

Therefore, the correct option is B.