Staggered and eclipsed conformers of ethane are:

Step 1: Define conformers

Conformers (or conformational isomers) are different spatial arrangements of a molecule that arise by rotation about a $\sigma$ bond, without breaking any bonds.

Step 2: Classify the relationship between staggered and eclipsed ethane

• They are not mirror images (they are related by rotation, not reflection)
• They are not polymers (same molecular formula, not polymerized)
• They are not enantiomers (enantiomers are non-superimposable mirror images)
• They are conformational isomers = Rotamers

Rotamers are conformers that differ by rotation about a single bond.

Step 3: Verify

Ethane conformations:

• Staggered: dihedral angle = 60°, most stable
• Eclipsed: dihedral angle = 0°, least stable
• Both arise from rotation about the $\ce{C-C}$ bond

Answer: Option (d) — Rotamers

Key Points to Remember:

• Conformers = same connectivity, differ only in rotation about $\sigma$ bonds
• Rotamers = conformers interconvertible by bond rotation
• Enantiomers require non-superimposable mirror image relationship
• Conformers are NOT considered separate compounds