Which group of immigrants was targeted by the Immigration Act of 1917 for being "undesirable"?

The Immigration Act of 1917 specifically aimed to restrict immigration from certain groups deemed "undesirable," focusing primarily on individuals from Asia and those with particular health issues or mental conditions. This legislation introduced a literacy requirement and created a list of "undesirable" categories that included people from the Asian continent because they were viewed as incompatible with American values and society at the time. The act also targeted individuals who were mentally ill or physically incapacitated, believing that they could burden social services or threaten public health. This legislation is part of a broader context in which various immigrant groups faced increased scrutiny and restrictions based on prevailing nativist attitudes and fears about immigration during that period.

The other choices do not accurately reflect the specific intent and scope of the Immigration Act of 1917, as it did not explicitly target individuals from Europe, South America, or Africa in a comparable manner. Instead, its focus was primarily on Asian immigrants along with those suffering from health issues.