A cloud administrator has been alerted to an issue where a critical application becomes unresponsive at random intervals. Monitoring tools show that the instance hosting the application is reaching its maximum processing capacity sporadically. What is the BEST immediate action to improve the application's responsiveness?
Allocate additional processing power to the instance.
Modify the instance's security group configurations.
Initiate a comprehensive code review to optimize application performance.
Reboot the instance to clear any temporary processing bottlenecks.