Reducing price to non conformity

Dalg Co contracted with Vincent Co under the UN Convention on Contrads for the international Sale of Goods to deliver 100 items. When the items were delivered it was found that 30 were significantly damaged and unrate Which TWO of the following remedies are available to Vincent Co? 1.Return the 30 damaged items and require them to be repaired 2.Return the 30 damaged items and require 30 substitute items to be delivered instead 3.Return the 100 items and declare the contract avoided 4.Keep the 100 items and only pay 70% of the contracted price 1&2 is correct but why is 3&4 incorrect he can return and declare avoided since they were significantly damaged