Answer:
A. Focus
Step-by-step explanation:
Focus can simply be defined as the way in which a person draws someone attention to a particular things in order for the person to focus or pay his or her attention to it.
Focus as well means to pay full concentration or attention on something Example a person may decide to pay his or her full attention on something of interest that will benefit him or her which is why Mrs Barnhart was using FOCUS as the display on the overhead in order to draw her student attention to the topic "main idea" she was about to discuss to them.