Six persons A, B, C, D, E and F are sitting around a circular table facing the centre. E is fourth to the left of D, who is to the immediate left of B. A is to the immediate left of C. F is not sitting adjacent to E. Who is sitting second to the right of F?

Let's trace the arrangement around the circular table based on the constraints. Facing the center implies standard left-right circular conventions.
Let's arrange them relative to each other. "E is fourth to the left of D." In a 6-seat circle, being 4th to the left is identical to being 2nd to the right.

"D is to the immediate left of B." This fixes the relative layout of B and D.

"A is to the immediate left of C." This means A and C must occupy adjacent seats.

"F is not sitting adjacent to E."

Following these constraints, the unique valid clockwise positioning sequence around the table is:
D, B, F, E, C, A

Let's locate F in this sequence. To find who sits second to the right of F, we move two positions in the counter-clockwise direction (right) from F, which lands directly on E.