Final answer:
The SIM card is the component in cellular-enabled tablets and smartphones that contains the device's telephone number and identifies it to the carrier.
Step-by-step explanation:
The component in most cellular-enabled tablets and smartphones that contains the device telephone number and identifies the device to its carrier is the SIM card (a). SIM stands for Subscriber Identity Module, and this small chip holds the International Mobile Subscriber Identity (IMSI) and the related key used to identify and authenticate subscribers on mobile telephony devices such as tablets and smartphones. It is this SIM card that allows a phone to connect to the network and placed calls, send messages, and use data services. The CPU (b) is the central processing unit, handling the computations of the device; the battery (c) provides power; and the camera (d) is used to take photos or videos.