Among the levels of module strength (cohesion) used to evaluate module independence, which has the highest strength and is considered most desirable?

Answer: A. Functional cohesion

Module strength expresses how closely the processing inside one module is related; the stronger it is, the more independent the module and the easier it is to change and test. In decreasing order of strength, it is classified as functional, informational, communicational, procedural, temporal, logical and coincidental cohesion. Functional cohesion is the state in which a module implements just one clear function. Logical cohesion groups several related functions that are selected by an argument, and coincidental cohesion groups unrelated processing into one module by chance.

• A. Correct. The module implements just one clear function, which is the highest strength.
• B. Several related functions are selected by an argument; this is classified among the weaker levels.
• C. Unrelated processing is grouped together by chance; this is the lowest strength.