Phase difference in a wave depends on separation and wavelength Steps:

• Identify wavelength from given wave properties: distance between crest and adjacent trough is λ/2 horizontally or sqrt((λ/2)^2 + (2A)^2) as straight-line distance.
• The given distance of 0.5 m is ambiguous without specifying if it's horizontal or straight-line, and no amplitude A is provided.
• Phase difference φ = (360° × d) / λ, with d = 1.0 m, but λ cannot be uniquely determined.
• Without clear λ, φ cannot be calculated numerically.

Why D is correct:

• Not applicable; insufficient data to select any option confidently.

Why the others are wrong:

• A: 55° assumes arbitrary small phase shift unrelated to given distances.
• B: 110° might stem from incorrect λ ≈ 3.3 m, ignoring wave definition.
• C: 160° could result from mistaking 0.5 m as λ/4, yielding λ = 2 m and φ = 180°, but adjusted wrongly.

Final answer: Not enough information.