The correct answer is: D. did not pay attention to Sameer’s request.
The counter clerk was very busy, so she did not have time to pay attention to Sameer’s request. She was probably focused on helping other customers or on completing her own tasks.
The other options are incorrect because they do not make sense in the context of the sentence. For example, option A, “can, help,” is incorrect because the counter clerk did not have the ability to help Sameer. Option B, “could, respect,” is incorrect because the counter clerk did not have the opportunity to respect Sameer’s request. Option C, “had, cash,” is incorrect because the counter clerk did not have the money to give Sameer cash. Option E, “certainly, acceptance,” is incorrect because the counter clerk did not certainly accept Sameer’s request.