Consider the following situation. It takes 10 (20) workers to produce 1 ton of pork (rice) in Vietnam, and 30 (15) workers to produce 1 ton of pork (rice) in Thailand. Both countries have 600 workers. Which statement is right about Vietnam's PPF? Vietnam can produce 40 tons of rice at most. Vietnam can produce 80 tons of pork at most. Vietnam can produce 30 tons of port and 15 tons of rice. Vietnam can produce 20 tons of port and 25 tons of rice.