Step-by-step Solution:

Quick Solution

The best way to solve this is to use the specific condition given in the question ("A is standing on Step 1") to determine the exact position of each person.

1. Placing A and C

• We are given as a specific condition: "A is standing on Step 1".
• We use the general rule: "The step number, on which A is standing, is two less than that of C" (which means A = C - 2).
• Plugging in A's position: 1 = C - 2. Solving for C gives us C = 3.
• Conclusion: A is on Step 1 and C is on Step 3.

2. Placing B and D

• The general rule for B and D is: "The step number on which B is standing is one more than that of D" (B = D + 1). This means they stand on adjacent steps.
• The steps currently available are 2, 4, 5, and 6. The only pairs of available adjacent steps are (4, 5) and (5, 6).
• This gives two possibilities: (D=4, B=5) or (D=5, B=6).
• However, the question adds another condition: "B is not standing at Step 6".
• This eliminates the second possibility. Therefore, the only valid placement is: D is on Step 4 and B is on Step 5.

3. Evaluating the Options

So far, we have determined the following positions: A is on step 1, C is on step 3, D is on step 4, and B is on step 5. Now we can check the statements:

• A. B is standing on step 2. (False, B is on 5)
• B. C is standing on step 4. (False, C is on 3)
• C. E is standing on step 3. (False, C is on 3)
• D. D is standing one step higher than C. (D is on step 4 and C is on step 3. This statement is True.)

Final Answer: The true statement is that D is standing one step higher than C.