In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as 'a' for Yes or 'b' for No.
Q: Question: What type of geological process forms the rock that is the roof of the church? Passage:St Jude's is constructed in yellow sandstone ashlar with a slate roof. Its plan is rectangular and consists of a nave and chancel in one cell with no division between them, a vestry attached to the east end of the chancel, and a bellcote on the gable at the west end. Above the bellcote is a canopy decorated with crockets. The west front contains a double door, above which is a triple lancet window with a circular window over it. At the corners are square turrets which become octagonal as they rise, and each is surmounted by a spire. On each side of the church are five pairs of lancet windows, each pair being separated by a buttress. Above the vestry at the east end is another triple lancet window, over which is a cricketed gable.

A:
b