Which of the following statements is true?

(A). A consultant is a professional who provides advice in a particular area of expertise such as marketing, finance, economics, accountancy, technology, law, human resources, medicine, public affairs, communication, engineering, etc

(B). An Information broker is an individual or an organization that on-demand seeks to answer queries using resources available in various places.

(C).  An expert is a person who possesses sound knowledge of a discipline, techniques, etc.

(D). A Extension Worker has the knowledge, relevant skills, competence, and expertise to give a talk, guidance or first-hand information in a given subject or area