During World War II, some British colonial officers questioned the economic and political viability of the southern provinces as separate from northern Sudan. Britain also had become more sensitive to Arab criticism of the southern policy. In 1946, the Sudan Administrative Conference determined that Sudan should be administered as one country. Moreover, the conference delegates agreed to readmit northern administrators to southern posts, abolish the trade restrictions imposed under the "closed door" ordinances, and allow southerners to seek employment in the north. Khartoum also nullified the prohibition against Muslim proselytizing in the south and introduced Arabic in the south as the official administration language.