Final answer:
The correct representation for 35% of the classrooms being painted green is A) 35/100, 0.35, 35%.
Step-by-step explanation:
The question involves calculating the percentage of classrooms that the students decided to paint green out of a total of 100 classrooms. Given that 35% of the classrooms are to be painted green, the different representations of this percentage would be fraction form (35/100), decimal form (0.35), and percentage form (35%). Therefore, the correct answer to the question is A) 35/100, 0.35, 35%.