Select the statement from "The Secret Life of Walter Mitty" that uses a formal tone.

A. "I've read your book on streptothricosis," said Pritchard_Mitford, shaking hands. "

B. "Rev her up to 8,500!"

C. "The Old Man ain't afraid of Hell!"

D. "Wrong lane, Mac," said the parking-lot attendant, looking at Mitty closely.

At first I thought it was A but formal language does not have contractions (I've) so thinking D now any opinions would be appreciated thank you.