Final answer:
The symbol μ, pronounced 'micro,' represents a factor of 10⁻⁶, as in a micrometer (1 μm) being 10⁻⁶ meters.
Step-by-step explanation:
The symbol μ in the context of strain is spoken as "micro," and it denotes a factor of 10⁻⁶. So the correct answer to the question is c) 10⁻⁶. This prefix is often used in the sciences to indicate a sub-unit of a meter, gram, or liter. For instance, one micrometer (1 μm) is 10⁻⁶ meters, and a microgram (μg) is 10⁻⁶ grams. Understanding these prefixes is important for working with measurements at a microscopic scale or in fields such as microbiology where small measurements are common.