1. Assuming that 100 houses are to be allocated to 300 households, what methods can be used? Please use economic principles to compare and analyze the impact of at least two methods on the level of social welfare (efficiency of resource allocation).
2. Please judge whether the following two sentences are correct? And explain your reasons.

a. If a tax cannot obtain tax revenue, it will not produce deadweight losses.

b. The sales volume increases after the price of the product is reduced, so the sales revenue received by the manufacturer also increases.