Answer:
b. 300 radios, 100 televisions in Radioland and 100 radios, 300 televisions in Teeveeland.
Step-by-step explanation:
Radioland produce 4*100 = 400 radios 
 Teeveeland produce 4*100 = 400 TVs 
 If Teeveeland produces only Teevees and radioland only radios (I think this is what he question suggests by "Also supposethat each country completely specializes in producing the good in which it has a comparative advantage") then Answer is as follows 
 Hence max consumption of Radioland = 300 radios + 100TVs 
 Hence max consumption of Teeveeland = 100 radios + 300TVs
Hence, 300 televisions and 100 radios in Teeveeland and 300 radios and 100 televisions in Radioland. that is option B is correct.