The size he should bring more of is small and is denoted as option A.
This is a term which refers to the number of goods sold within a given period of time.
Small size has the smallest remaining which is 9 when the difference between the number sold and number put up for sale is calculated. This is therefore why bringing more of small size will ensure he doesn't run out of stock in the next event as more people prefer it.
Read more about Sales here https://brainly.com/question/24951536
#SPJ1