Which of the following is a sign of authority in an author?

a)the author is a commercial source.

b)the author has an established record of research.

c)the author is anonymous.

d)all of the above.

B

Explanation:

A commercial source might have a reason to lie, or bend the truth, for financial gain. With an anonymous author, you can't identify them, so you don't know if they would tell the truth or be right or not. An established record of research proves that the author knows how to find and state facts, and cares that their writings are accurate.

beethoven's first public performance in vienna was on march 29, 1795. he gave a piano concert, or akademie, in vienna's burgtheater as part of an event organized by joseph haydn (probably op. 15). in these early years, beethoven's success as a composer was closely tied to his career and renown as a piano virtuoso.

explanation:

can you rephrase the question? was there a picture to go along with it?