Phonological variation in sign languages refers to differences in the form or production of signs, similar to how phonological variations occur in spoken languages (like dialectal differences in pronunciation).
Based on this definition, the best option that represents an example of phonological variation would be:
B. doing a sign on one hand instead of two.
This option indicates a variation in the production of a sign, similar to how phonological variations might manifest in different accents or dialects in spoken languages.