reasoning · 2026-09-11

Four people (A, B, C, D) wait in line. A is directly in front of B. C is directly behind D. A is not first. Who is first in line?

Answer: c

A and B must be adjacent (AB). D and C must be adjacent (DC). Since A is not first, the only way to arrange them in 4 spots is DCAB. Therefore, D is first.

Model answers

• gpt-oss-20b (openai/gpt-oss-20b): c
• qwen-3-8-27b (qwen/qwen3.8-27b): c
• nemotron-3-super (nvidia/nemotron-3-super-120b-a12b:free): c
• gemini-3-8-flash (gemini-3.8-flash-low): c
• gemini-3-1-pro (gemini-3.1-pro-high): c
• claude-opus-4-6 (claude-opus-4-6-thinking): c