This paragraph describes a natural process, so it helps to lay out the actual stages of glacier formation first and then match each sentence to a stage.
The process has four stages: first, where glaciers exist in general, then how they start forming, then how they grow over time, and finally how that growth turns into ice. "Most glaciers are found near the Poles" fits the first stage, since it is a general fact about glaciers rather than a step in their formation, and it also introduces the word "glaciers," which the pronoun "they" in the next sentence needs. "They begin to form when snow remains in the same area all year round" fits the second stage, describing the starting condition. "In the following years, more layers of snow add up to the existing mass" fits the third stage, the gradual buildup. "Consequently, the weight of the snow compresses and turns into solid ice" fits the last stage, since "consequently" signals a result that needs the buildup from the sentence before it.
Matching each sentence to its stage in the natural process gives the order: where glaciers are found, how they start, how they build up, and how they turn to ice.
So, the correct answer is cdab.
Another way to work through this is to track only the connecting words, pronouns, and repeated nouns in each sentence, apart from the overall meaning.
Chaining only the words "they," "the existing mass," and "consequently" back to what they point to confirms the same sequence.
So, the correct answer is cdab.