Final answer:
The diminutive of Bridget that usually refers to a fussy old woman is Biddy.
Step-by-step explanation:
The diminutive of Bridget that usually refers to a fussy old woman is: b) Biddy. The term "Biddy" is a diminutive or nickname derived from Bridget. It has been historically used to refer to an elderly woman, often with a connotation of fussiness or old-fashioned habits. While it can be used affectionately, it may also carry a somewhat stereotypical image of an older, perhaps conservative, woman. The usage of such diminutives is culturally influenced, and interpretations may vary based on regional language conventions and historical contexts. Options a (Granny), c (Nanny), and d (Auntie) are also terms for older women, but "Biddy" specifically stems from Bridget in this context.