Summarize Argument
The linguist concludes that Austronesian-speaking peoples originated in Taiwan before migrating elsewhere. This is because Austronesian languages must all have one point of geographic and linguistic origin, and because Taiwan is where Austronesian languages have been spoken the longest.
Identify Conclusion
The conclusion is where Austronesian-speaking peoples originated: “Austronesian-speaking peoples originated in Taiwan and later migrated to other islands.”
A
The Austronesian family of languages has four subfamilies, three of which are found only among indigenous peoples in Taiwan.
This is context for the argument. There’s no support for this statement, so it can’t be a conclusion.
B
Wherever most subfamilies of the Austronesian family of languages have been spoken longest is probably the homeland where Austronesian languages originated.
This is a sub-conclusion that acts as a premise. Since Taiwan is probably the homeland where Austronesian languages originated, Austronesian-speaking peoples likely migrated from Taiwan.
C
Taiwan is probably the homeland where Austronesian languages have been spoken longest.
Our conclusion is about the likelihood that Austronesian-speaking peoples migrated from Taiwan. This answer is a premise that contributes to that conclusion.
D
Austronesian-speaking peoples originated in the homeland where Austronesian languages have been spoken longest.
This is a premise that supports the conclusion. Taiwan is where Austronesian languages have been spoken the longest, and is thus where Austronesian-speaking peoples originated.
E
Austronesian-speaking peoples probably originated in Taiwan and later migrated to other islands.
The linguist establishes Taiwan as the geographic and linguistic origin of Austronesian-speaking peoples. Since Austronesian-speaking peoples are spread broadly from Madagascar across the Pacific, the linguist concludes that they migrated from their origin, Taiwan.