Chiral carbons require four different substituents Steps:

• Draw the structure of 2,2,4-tetramethylhexane as CH₃–C(CH₃)₂–CH(CH₃)–CH(CH₃)–CH₂–CH₃, with the main chain of six carbons and four methyl branches.
• Identify tertiary carbons (with one H): C3 and C4, as C2 is quaternary and others are primary/secondary.
• For C3, check substituents: H, CH₃, C(CH₃)₃ (from C2), CH(CH₃)CH₂CH₃ (from C4); all different, so chiral.
• For C4, check substituents: H, CH₃, CH(CH₃)C(CH₃)₃ (from C3), CH₂CH₃ (from C5); all different, so chiral. Why B is correct:
• The molecule has exactly two carbons (C3 and C4) each bonded to four distinct groups, per the definition of a chiral center. Why the others are wrong:
• A: Underestimates; both C3 and C4 qualify as chiral.
• C: Overestimates; only two tertiary carbons have four different substituents, not three.
• D: Overestimates; no additional chiral centers exist, as C2 has identical methyl groups.

Final answer: B