Topic: Conjunction,

Best Answer Explained in Below-:

The correct answer to the sentence, "Our teacher teaches Mathematics ---- English," is **B) besides**. The use of "besides" in this context indicates that Mathematics and English are both subjects taught by the teacher, emphasizing that they are additional areas of instruction.

The word "besides" typically means "in addition to" or "apart from," making it suitable for sentences where one item is added to another. In this case, it conveys that the teacher teaches both Mathematics and English, with the understanding that both subjects are part of the curriculum.

In contrast, the other options do not fit appropriately in this context. "Across" implies an interaction that is not relevant here, while "beside" generally denotes physical proximity, which does not apply to teaching subjects. The choice "both" isn't grammatically correct as it cannot be used to fill the blank directly since it doesn't fit the syntactical structure of the sentence.

Thus, "besides" effectively communicates the dual nature of the subjects taught, highlighting the teacher’s role in providing a broader educational experience.