emergency: added sentence

some toefl reading requires to add one sentence, I am confused which place should the sentence be added? for example: I know the sentence must be added in after A and before B, but which choice can I click? A or B?

please tell me!!!!!

In the real test there will be some SQUARES you just need to clink on the right square

I know the sentence must be added in after A and before B,

that means click sentence B?