Mike Authorizes His Agent,Ben to Borrow a Sum of $10,000

Multiple Choice

Mike authorizes his agent,Ben to borrow a sum of $10,000 on his behalf from the National Bank.Ben signs his name to a note without disclosing that the signature was on behalf of Mike.Who is liable on the note?

A) Only Mike is liable.
B) National Bank is liable.
C) Both of them are liable.
D) Only Ben is liable.