An artist creates mosaics using stone tiles provided by his clients. A mathematician challenges him to make a series of large mosaics and a series of small mosaics following a few mathematical restrictions. Each large mosaic must have 85 tiles and each small mosaic must have 75 tiles. The total number of tiles in each series must be identical. What is the total number of mosaics the artist will create?

(1) The total number of mosaics in the series is less than 50.

(2) The number of small mosaics in the series is a prime number.

Answer: D

Source: Manhattan GMAT