Final answer:
Old English dropped case endings on nouns primarily due to the evolution of linguistic structure, along with influences from contact with Latin and Norman French. Simplification of language structure and adaptability to changing communication needs contributed to this linguistic change.
Step-by-step explanation:
The dropping of case endings on nouns in Old English occurred due to the evolution of linguistic structure, among other factors. Over time, languages tend to simplify and evolve, influenced by various political, social, and linguistic factors. While simplification of the language (Option A) is a broad trend observed in linguistic history, options B and C, concerning the influence of Latin grammar and borrowing from French grammar, also played roles in the transformation of English—the Germanic language was transformed through contact with Latin speakers, and later the Norman Conquest introduced French influence. However, the direct cause of the loss of case endings is more about overall linguistic evolution than direct borrowing from another language's grammar.
This simplification and evolution are in line with broader linguistic trends, where contact with other languages and cultures, migration, and the evolving needs of communication lead to changes in a language's structure. This natural process of language change can be seen in modern times too, where technical advancements and cultural shifts quickly introduce new vocabulary and changes in language usage.