Formal language is also called "proper language" because it is the type of language you would use when first meeting someone or giving a speech at a high class place so the correct answer is:
<span>B) Have I convinced you that the study of grammar is important and well worth your effort? </span>
big foot......................
A. present the characters and the situation
Uno reverse.......................0
The answer is D. Infancy and old age.
I hope this helps. :)