PLEASE HELP ASAP!! Please only answer if you have read Sneaker Nation.
Carro writes, “Companies began zeroing in on the most talented athletes and enlisting them to market new designs.” Based on context clues, what does the phrase “zeroing in” mean? *

A. to take something away gradually
B. to give money for
C. to dismiss from employment
D. to direct all of one’s attention to someone or something