What angle range defines opposite or reciprocal courses?

The correct answer, which identifies the angle range defining opposite or reciprocal courses, is determined by understanding the relationship between two courses as they relate to each other on a compass. Opposite or reciprocal courses are those that directly oppose one another, meaning they are 180 degrees apart.

In nautical and aeronautical contexts, when two courses are considered reciprocal, they effectively point in opposite directions. For example, if you are traveling on a course of 40 degrees, the reciprocal course would be 220 degrees (which is 180 degrees added to 40 degrees, or alternatively, derived from rotating in the opposite direction).

The angle range that encompasses angles from 135 to 180 degrees represents this direct opposition clearly, as it includes angles that demonstrate how far apart two courses can be when they are facing in completely opposing directions. The other ranges do not accurately reflect this opposition, either being too close or not reaching the necessary separation needed to be considered as reciprocal courses.

In summary, the range of 135 to 180 degrees defines the critical aspect of opposite courses due to their direct separation of 180 degrees, highlighting the fundamental principle that courses that are a half-circle apart will lead to reciprocal navigation.