The following ad copy appeared in the local newspaper ad for the Gleason Guitar Store on Thursday.

"Gleason guitar string sets heavy, medium, or light gauge, for sale at $5. Out they go tomorrow on Super Sale Friday; First Come First Served. Doors open at 10 am.

"Gleason Replica Model Catocaster guitars for sale at $500."

a.) The guitar string ad is an invitation to negotiate and the Catocaster ad is an offer.

b.)The guitar string ad is an offer and the Catocaster ad is an invitation to negotiate.

c.) The guitar string set ad and Catocaster guitar ad are both invitations to negotiate

D)	The guitar string set ad and Catocaster guitar ad are both offers.