Five friends P, Q, R, S and T are standing in a row facing East. Who is standing at the extreme right end?
I. Only P is between S and T. R is to immediate right of T.
II. R is between T and Q.

Options

A. the data in statement I alone are sufficient to answer the question, while the data in statement II alone are not sufficient to answer the question,
B. the data in statement II alone are sufficient to answer the question, while the data in statement I alone are not sufficient to answer the question,
C. the data either in statement I alone or in statement II alone are sufficient to answer the question,
D. the data in both statements I and II together are necessary to answer the question.

Explanation

To solve the problem of determining who is standing at the extreme right end among the five friends P, Q, R, S, and T, we will analyze the given statements step by step.

### Step 1: Analyze Statement I
The first statement tells us:
- "Only P is between S and T."
This means that the arrangement must be either S-P-T or T-P-S.

### Step 2: Analyze Statement I Further
Next, we have:
- "R is to the immediate right of T."
If we assume T is on the left, then R must be placed immediately to the right of T. Therefore, the arrangement based on the first statement can be:
- If T is at position 1, then R must be at position 2, and P must be at position 3, leading to S at position 4. This gives us T-R-P-S. However, this does not satisfy the condition of P being between S and T.

Instead, if we place T at position 2, then R must be at position 3, and P must be at position 4, leading to S at position 1. This gives us:
- S-T-R-P (with one position left for Q).

### Step 3: Analyze Statement II
Now, let's look at the second statement:
- "R is between T and Q."
This means R must be in the middle, so the arrangement must be T-R-Q.

### Step 4: Combine Both Statements
Now we need to combine both statements:
1. From Statement I, we have S-P-T or T-P-S.
2. From Statement II, we have T-R-Q.

Since R must be to the right of T, we can place them in the following way:
- S must be on the leftmost side, followed by P, then T, then R, and finally Q.

Thus, the arrangement becomes:
- S-P-T-R-Q.

### Step 5: Identify the Extreme Right End
In this arrangement, Q is at the extreme right end.

### Conclusion
Thus, the answer to the question "Who is standing at the extreme right end?" is Q.