The BEST characteristic that describes security mechanisms for mobile devices is easy to control through mobile device management. This is because mobile device management is a technique that allows organizations to centrally manage and secure mobile devices, such as smartphones, tablets, laptops, etc., that are used by their employees or customers. Mobile device management helps to enforce security policies, configure settings, install applications, monitor usage, wipe data, etc., on mobile devices remotely and efficiently. The other options are not characteristics that describe security mechanisms for mobile devices, but rather different aspects or factors that affect security mechanisms for mobile devices, such as weakness (B), inadequacy C, or reliability (D).