Comprehensive and Detailed in Depth Explanation:

Pairwise testing is a combinatorial test design technique in which test cases are designed to execute all possible discrete combinations of each pair of input parameters. This technique significantly reduces the number of test cases compared to exhaustive testing while still covering pairwise interactions.

To calculate the number of test cases:

Colour: 4 options

Model: 3 options

Gigabytes: 4 options

Connectivity: 2 options

Pairwise testing does not necessarily involve multiplying all options, as it aims to cover all pairs. Using an orthogonal array or pairwise tool, the minimum number of test cases that cover all pairs for these parameters is16. Hence, the answer isC (16).