A. The explorer who claimed Brazil was following a plan to sail far to the west to find and claim land for Portugal.
- this is not likely, as at the time lands "far" to the west belonged to Spain!
B. The explorer who claimed Brazil was able to do so because Brazil lay
east of the Line of Demarcation drawn at the Treaty of Tordesillas.
This is true! This treaty "split" the world among Spain and Portugal: and Portugal then pushed the boundary, making today's Brazil bigger
CA map of South America that shows the 1494 Line of Demarcation
explains why the people of Brazil speak a different language from most
of the people living in the rest of South America.
-well, yes, it can be said to be true: it shows that people east of the line of demarcation speak Portuguese, and then the line was not followed exactly which explains why people immediately west to this line also speak Portuguese: the line was "shifted"
So I think B and C
