Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Marlborough Brook Filter Beds - The Marlborough Brook Filter Beds are a series of water filtration beds near the mouth of Marlborough Brook where it enters Sudbury Reservoir near the town line between Marlborough and Southborough Massachusetts. The filter beds were constructed in 1895 as part of the reservoir construction to improve the water quality of Marlborough and Walker Brooks.
The answer to this question is:
Building