Yes it is, it has a period therefore a complete sentence.
Well being able to read a native language helps you communicate to others. Literacy skills help you express your thoughts, and solve problems.
The correct answer for the question that is being presented above is this one: "b. Mary had heard herself mentioned to Miss Bingley as the most accomplished girl in the neighbourhood; and Catherine and Lydia had been fortunate enough never to be without partners, which was all that they had yet learnt to care for at a ball"
