According to the federal Office of Consumer Affairs, ________.

A) letters from satisfied customers are the best evidence to support claims
B) failing to include important information is considered deceptive
C) marketing messages and websites cannot target children
D) offering a money-back guarantee is illegal

The federal Office of Consumer Affairs considers failing to include important information as deceptive. The other options are incorrect - there is no indication that letters from satisfied customers are the best evidence to support claims, that marketing messages and websites cannot target children, or that offering a money-back guarantee is illegal.