Mark is setting up a green energy consulting business. He sends out advertising brochures to all local area businesses. Lydia of Edmonton Solar Ltd. replies to Mark's ads and invites Mark to submit a proposal to Edmonton Solar Ltd. for a new marketing plan. Mark incurs some considerable expense and takes three weeks to complete the proposal. After submitting the proposal to Lydia, Mark reads in a blog that Edmonton Solar Ltd. awarded an exclusive marketing contract to another firm. Based on these facts, which of the following is true?

The invitation by Lydia shows a consensus to form a contract.

The invitation by Lydia is merely an invitation to treat and not an offer to make a contract.

The parties have agreed to all the required elements of a contract.

The court can infer an implied contract.

Lydia will have to pay Mark something for his effort.