What is evaluated regarding the vehicle's battery?

When evaluating a vehicle's battery during a Maryland state inspection, several critical aspects are assessed to ensure that the battery operates safely and efficiently. The correct choice highlights that the battery must be secure, free of corrosion, and in good working condition.

A secure battery prevents movement during vehicle operation, which could cause damage or lead to hazardous situations. Checking for corrosion is essential because corrosion can lead to poor electrical connections, resulting in starting issues or greater electrical system problems. Additionally, ensuring the battery is in good working condition means that it holds a charge properly and performs optimally in various conditions.

While other factors such as size, age, and frequency of checks may be important in other contexts, they do not directly address the essential safety and functionality requirements laid out in the state inspection guidelines. Therefore, the focus on the battery's security, cleanliness from corrosion, and overall condition is crucial for ensuring a reliable vehicle operation and is why this answer is correct.