Help with concentration pieces information?

I'm going to be applying for MCAD in the fall & I will be going to be showing my sketchbook & 10-15 pieces of work, I figure I might do concentration pieces for it? But I have grown up in a household & environment where I do not receive any real information regarding art things. SO SO SO, I was wondering if concentration pieces can be done in any style when it comes down to the actual drawings. Like realism or cartooning? Iunno does style matter or is it the actual technicality executed or something? ; __ ; I need help~?