Explanation:

- P is sitting in front of Q.

- This positions P and Q directly opposite each other in the circle.

- Q is sitting to the immediate right of T and immediate left of R.

- This indicates the order as T, Q, R going clockwise.

- P is to the left of U and right of S.

- This implies the order is S, P, U going clockwise.

- By combining both arrangements:

- The seating order is: S, P, U, T, Q, R.

- Who is sitting opposite to R?

- Since there are six people equally spaced, R will be directly opposite from U.

- The correct option:

- Option 4, U is opposite to R.