Q. What does this code do?

@media only screen and (max-width: 768px) {
    class*="col-"] {
        width: 100%;
    }
}

• (A) Error occured
• (B) When the screen gets larger than 768px, each column should have a width of 100%.
• (C) When the screen gets smaller than 768px, each column should have a width of 100%.
• (D) All of above