Bidding is a bidding method in which the bidder does not go through the general transaction negotiation process before buying or selling bulk commodities, contracting out a construction project, or cooperating in a certain business. Which of the following transaction methods is a tender? ['Boss Zhang plans to sell suburban villas and declares that they can be negotiated on the basis of not less than 2 million yuan.', 'Zhang intends to bid for the construction project of the villa complex in the city and issue a notice to the units with corresponding construction qualifications inside and outside the province.', "A confidential manager of Boss Zhang's company is missing for some reason, he decided to offer a reward of 100,000 yuan to find the insider.", "Boss Zhang wants to throw 60% of his company's stock for 150,000 yuan."]