Five friends A, B, C, D, and E are sitting in a row facing north. C is to the right of A. B is to the left of D. D is to the left of A. B is to the right of E. Who is sitting at the center?

Seven people, C, D, E, F, W, X and Y, are sitting around a circular table facing the centre. Only two people sit between C and D when counted from the left of D. X sits to the immediate right of D. Only three people sit between D and E. F sits to the immediate right of W. How many people sit between Y and F when counted from the right of F?

Five students (A, B, C, D, and E) are standing in a line during a school assembly. C is standing exactly behind D. E is not standing behind B. A is standing ahead of C but not ahead of B. If 'behind' means being exactly next to someone's back and 'ahead' means anywhere in front of someone, who among the five students is standing at the third position from the front?