The correct answer is B. The Bristol Glacier is older than the Camden Glacier.
Explanation
The formation of glaciers has three stages. The first is the accumulation in which the snow falls in one place and accumulates there and forms the glacier. The second is compaction in which new layers of snow accumulate on top of the first ones, compacting the lower layers. The third is crystallization in which pressure and air cause snow to crystallize into glacial ice. Therefore, the age of a glacier can be known by its length, the older is the longer glacier. According to the above, if the length of the Bristol Glacier is greater than that of the Camden Glacier, it is because it is older. Then the correct answer is B.