Correct Answer: Be all ears

Solution : The correct choice is the fourth option.

"Be all ears" is an idiom that means to listen carefully and attentively. In the context of the sentence, it conveys the idea that Raima is paying close attention during her classes.

The meanings of the other options are as follows:

• "In accordance with" means in agreement or compliance with something.
• "By blazing a trail" means to be a pioneer or the first to do something.
• "By losing in a cloud" is not an idiom or expression in English.

Therefore, the correct sentence is: "Raima takes her classes while being all ears."