When writing equations. like the one's in the photo. in standard form, you must put the biggest exponent first. Then you put the second biggest exponent, and you keep going smaller and smaller until you get to the variable without an exponent (example= x) and then after that you put any numbers that don't have a variable (example= 3). Because of this A and C are not in standard form because A has its second biggest exponent at the end of the equation instead of in the middle and C has its "variable without an exponent (v) at the end instead of in the middle. And so, by looking at how the equations are ordered you can see that B and D are in standard form.
