Ahistorian compares transcripts of speeches delivered by powerful leaders throughout world history. these transcripts serve as which of the following

You didn't really provide any of the possible explanations why would a historian compare these transcripts which would enable for easier answering. In general, using transcripts from powerful leaders serve as primary evidence which give insight into the minds of important people of the past. 

The answer is william henry harrison pursued and defeated british forces retreating into canada.

Provide more information so i can answer your question; )