Histidine is an amino acid. What are the approximate bond angles 1, 2, and 3?
- A1: $109.5^\circ$, 2: $107^\circ$, 3: $90^\circ$
- B1: $120^\circ$, 2: $107^\circ$, 3: $109.5^\circ$
- C1: $120^\circ$, 2: $120^\circ$, 3: $90^\circ$
- D1: $120^\circ$, 2: $120^\circ$, 3: $109.5^\circ$