B
I think it should change into “The test subject will be observed for the next few days.”
The problems of listening to a lecture could go on and on. There are a copious amount of different variables that take place when a lecture is being orally presented. “Is the lecture interesting?” “Who is presenting the lecture?” “Who’s in the audience?” So very often we find ourselves bored while listening to a lecture due to the sheer fact of the presenters voice. The only problem that occurs while listening to a lecture is the personality and preference of the one who is listening.