Explanation:

A Micro computer, commonly known as a Personal Computer (PC), is typically a desktop unit designed to connect to a monitor, which historically resembled a television screen in size and form factor. Compared to larger systems like (c) Super mini computers or (d) Main frame computers, microcomputers are compact enough to fit on a desk and are often associated with a display unit similar to a television. (a) Optical refers to a technology, not a computer type. Therefore, 'Micro' ($ \text{b} $) is the most appropriate term for a 'television size computer' in common parlance, referring to its typical setup with a monitor.