Final answer:
Malaria significantly hindered European colonization of the African interior before the mid-19th century because Europeans had little resistance to the disease. Quinine usage and bacteriological advances eventually improved Europeans' ability to survive in tropical regions, facilitating greater colonization efforts. The correct option is b.
Step-by-step explanation:
The question "What was a major reason Europeans did not make extensive inroads into the African interior before the middle of the nineteenth century?" can be answered by option b. inability to protect themselves from malaria.
Malaria was a deadly disease that disproportionately affected Europeans compared to Africans, who had developed some measure of resistance. Before the 1950s, malaria was a significant barrier to European colonization of Africa due to Europeans' vulnerability to the disease.
It was not until the preventative use of quinine and advances in bacteriology that Europeans could survive in the tropical regions of Africa.
However, effective colonization was still limited until technological progress allowed for better communication and survival strategies in the 19th century. This allowed European countries to establish more significant presences within the African interior rather than just along the coasts.
The impact of malaria on colonization efforts is not unique to Africa; it was also a significant problem in British India, where irrigation and land clearing created breeding grounds for the disease's mosquito vector. The correct option is b.