Final answer:
Wickham shifts his attention from Elizabeth to another lady because he learns that Elizabeth is not as wealthy, revealing the financial motivations in romantic pursuits of the era.
Step-by-step explanation:
The reason Wickham turns his romantic attentions away from Elizabeth to another young lady is A) Wickham discovers that Elizabeth is not as wealthy as he thought.
This shift in attention underscores the theme of marriage and social standing prevalent in Jane Austen's time. Wickham's pursuit of financial security through marriage, rather than romantic affection, highlights the societal constraints and the reliance on marrying well for women's financial stability during the period the novel is set.