Which of the following examples can Emma show her mother as a form of a computer?

The choice of a coffeemaker programmed to start at a certain time is indeed a valid example of a computer because it processes information and follows instructions to perform a task. In this scenario, the coffeemaker incorporates a microcontroller or other form of computing technology that allows it to receive input (like the time set for operation) and execute its function accordingly (brewing coffee). This demonstrates the basic principles of how computers operate: they take inputs, process them, and produce outputs.

The other examples, while they may incorporate some technology, do not fit the definition of a computer as strictly. For instance, a smart refrigerator suggesting recipes does make use of computer technology, but the core function of the fridge is not primarily as a computing device. A landline telephone primarily facilitates communication without performing processing tasks typically associated with computers. Similarly, while a microwave oven with a timer uses digital controls, it operates more on preset functions rather than processing instructions in a manner characteristic of computers.