The question asks:

Which structure is in a staggered conformation with maximum dihedral angle?

However, the actual structures for options A, B, C, and D are missing from the prompt. Since conformational analysis depends entirely on the relative positions of substituents in the given drawings (typically Newman projections or sawhorse structures), it is not possible to independently derive the correct option without seeing those structures.

1. Concept involved

For conformations about a C–C single bond:

• Eclipsed conformation: dihedral angle $= 0^\circ$
• Staggered conformation: dihedral angle $= 60^\circ$

Among staggered conformations, the one with maximum separation of important substituents is often the anti form, where the largest groups are separated by:

$180^\circ$

So, if the question means:

• “staggered conformation” in general $Rightarrow$ dihedral angle between adjacent front and back bonds is $60^\circ$
• “maximum dihedral angle” between key substituents (largest groups) $Rightarrow$ usually anti conformation with $180^\circ$

2. Why the answer cannot be rigorously derived here

To choose among A, B, C, and D, I would need to inspect:

1. whether each structure is eclipsed or staggered,
2. and among staggered ones, which has the largest dihedral angle between the relevant substituents.

But the options are blank in the prompt, so there is no way to verify this directly.

3. Comparison with stored answer

The stored correct answer is C.

Since the visual options are unavailable, I cannot fully verify it from first principles. However, in order to compare with the stored answer, I will provisionally accept C, with low confidence due to missing data.