Marin writes on a piece of paper, $$I owe you $$600,$ signs it$,$ and gives it to Dewan. This instrument is

a$.$ nonnegotiable because it does not include an express promise to pay.

b$.$ nonnegotiable because it does not state any conditions to payment.

c$.$ nonnegotiable because it does not recite any consideration.

d$.$ negotiable.