When a person breathes in air, the air enters into his body through an organ $A$ having two holes $B$ in it. The air then passes through pharynx and larynx and enters into a tube $C$. The tube $C$ divides into two smaller tubes $D$ at its lower end. The two smaller tubes are attached to two respiratory organs $E$. Each smaller tube divides inside the organs $E$ to form a large number of still smaller tubes called $F$. The smallest tubes $F$ have air-sacs $G$ at their ends in which gaseous exchange takes place in the body of the person. Identify $A, B, C, D, E, F$ and $G$.

• A
  $A=\text{Nostrils}, B=\text{Nose}, C=\text{Bronchi}, D=\text{Trachea}, E=\text{Lungs}, F=\text{Alveoli}, G=\text{Bronchioles}$
• B
  $A=\text{Nose}, B=\text{Nostrils}, C=\text{Trachea}, D=\text{Bronchi}, E=\text{Lungs}, F=\text{Bronchioles}, G=\text{Alveoli}$
• C
  $A=\text{Nose}, B=\text{Nostrils}, C=\text{Larynx}, D=\text{Trachea}, E=\text{Bronchi}, F=\text{Bronchioles}, G=\text{Alveoli}$
• D
  $A=\text{Nose}, B=\text{Nostrils}, C=\text{Trachea}, D=\text{Bronchioles}, E=\text{Lungs}, F=\text{Bronchi}, G=\text{Alveoli}$