Which of the following is not a congruence transformation?

Usually, when people talk about "rocky” relationships, it’s with a frown, but mine has enriched my life. i became fascinated with rocks when i was really young, and throughout my childhood you could usually find me with my pockets bulging from whatever stony treasures i’d scavenged that day. when my science teacher taught us a unit on geology, i realized that my fascination could become an exciting career that could also me make good money. obtaining an internship to work on the geological exhibit at the museum is an important step on my road to being a geologist. the best description of the writer’s point of view is that the person is eager to make a lot of money in a museum internship. insistent that geology should be taught as part of every science course. hopeful to be able to further the goal of eventually becoming a geologist. concerned that people do not generally relate well to the study of geology.

Aman lives on the twelfth floor of an apartment building. every morning he takes the elevator down to the lobby and leaves the building. in the evening, he gets into the elevator, and, if there is someone else in the elevator -- or if it was raining that day -- he goes back to his floor directly. otherwise, he goes to the tenth floor and walks up two flights of stairs to his apartment.

This expert shows that unlike zaroff, rainsford has still retained his sense of