Unfortunately, Variants can only handle up to 3 options, though of course each option can have as many different buyer-selectable values as you wish. Do all 4 of your options need to affect the stock tracking? If so, you might consider combining two of them into a single option -- e.g.:
* Fabric+logo colors (oatmeal+blue, oatmeal+pink, cream+blue, cream+pink)
* Size (XXS, XS, S, M, L, XL, XXL)
* Style (women's tank, unisex v-neck, men's crewneck)