1/3 of the dimensions means to divide the dimensions by 3. This is to figure out what 1/3 of the dimensions are. Our length is 6, and our width is 9. Let's divide our length first. 6/3 = 2. Our length with 1/3 of it's original dimensions is 2. Let's divide our width now. 9/3 = 3. Our width with 1/3 of it's original dimensions is 3. Our dimensions are 2 by 3. Your answer is A.) 2 in. by 3 in. I hope this helps!