Determine the correctness or otherwise of the following Assertion $[a]$ and Reason $[r]$
Assertion: Significant combustion of coke takes place only if it is heated at higher temperature in presence of air.
Reason: $C+O_{2}{\rightarrow} CO_{2}$ is an exothermic reaction.
- Both $[a]$ and $[r]$ are true and $[r]$ is the correct reason for $[a]$
- Both $[a]$ and $[r]$ are true but $[r]$ is not the correct reason for $[a]$
- $[a]$ is correct but $[r]$ is false
- Both $[a]$ and $[r]$ are false