Mixture M's composition cannot be determined

Steps:

• Question asks for substances in mixture M but provides no description or data on M, P, Q, or R.
• Choices reference P, Q, R without definitions or experimental evidence.
• No tests, reactions, or properties are given to identify components.
• Not enough information to select any option confidently.

Why B is correct:

• Not enough information; cannot verify without context like chromatography or solubility tests.

Why the others are wrong:

• A: Not enough information; no evidence for three substances.
• C: Not enough information; no indication of only Q.
• D: Not enough information; no confirmation of only P.

Final answer: Not enough information.