Which of the Following Scenarios Will Amount to the Making

Which of the following scenarios will amount to the making of an offer?

A) Jasper telephones Rupert and asks whether he would sell his barbecue for $500.
B) Mimi emails Rose and inquires whether she has any Dalmatian puppies for sale.
C) James places a sign on his fruit stall stating that he will sell his remaining watermelons to the first 10 customers for $1 each.
D) Aubrey places an advertisement in the local newspaper for sale of his skateboard for $50 or the nearest offer.