Here's a problem to solve: Which of these chemical equations demonstrates the law of conservation of mass as it applies to the combustion of ethane?

Among the 4 following options, which is the correct answer?

- A: C_{2}H_{6} + 3O_{2} -> 2CO_{2} + 3H_{2}O
 
- B: C_{2}H_{6} + 5O_{2} -> 2CO_{2} + 3H_{2}O
 
- C: 2C_{2}H_{6} + 5O_{2} -> 4CO_{2} + 4H_{2}O
 
- D: 2C_{2}H_{6} + 7O_{2} -> 4CO_{2} + 6H_{2}O
 