Which of the following factors favor the formation of oxyhemoglobin in alveoli?

1. A
   High $p{\text{O}}_2$ and lesser ${\text{H}}^{+}$ concentration
2. B
   Low $p{\text{CO}}_2$ and high ${\text{H}}^{+}$ concentration
3. C
   Low $p{\text{CO}}_2$ and high temperature
4. D
   High $p{\text{O}}_2$ and high $p{\text{CO}}_2$