How does scale change on a normal Mercator chart?

Question

Question ATPL - Airline Transport Pilot license - General Navigation

QuizVDS · Accepted Answer

Expands directly with the secant of the latitude.

QuizVDS · Answer

Correct on the standard parallels, expands outside them, contracts within them.

QuizVDS · Answer

Expands as the secant of the E/W great circle distance.

QuizVDS · Answer

Expands as the secant^2 (1/2 co-latitude).

Id 240 - ATPL - How does scale change on a normal Mercator chart?