The entrance test for various courses aoffered by the Banaras Hindu university , Varansi are of moderate level. There are a number of good books by many authors available in the market which you can buy and study from . There are books of arihant publications available in the market you can buy them easily online or from any book store near you.
For all inforamtions / queries about admissions to BHU and their entrance test you can visit - https://university.careers360.com/articles/bhu-uet
Hope it helps