<h2>Hello!</h2>
The answers are:
C) 
D) 
F) 
<h2>Why?</h2>
To know which of the products results in a difference of square, we need to remember the difference of squares from:
The difference of squares form is:

So, discarding each of the given options in order to find which products result in a difference of squares, we have:
<h2>
A)</h2>

So, the obtained expression is not a difference of squares.
<h2>
B)</h2>

So, the obtained expression is not a difference of squares.
<h2>C)</h2>

So, the obtained expression is a difference of squares since it matches with the form of the difference of squares.
<h2>D)</h2>

So, the obtained expression is a difference of squares since it matches with the form of the difference of squares.
<h2>E)</h2>

So, the obtained expression is not a difference of squares
<h2>F)</h2>

So, the obtained expression is a difference of squares since it matches with the form of the difference of squares.
Hence, the products that result in a difference of squares are:
C) 
D) 
F) 
Have a nice day!