Concept:Sayyid Said used diplomatic measures to attract European merchants and boost Zanzibar’s trade.
Explanation:Sayyid Said wanted to expand commercial relations with Europe.
He signed commercial treaties with European nations.
To make these treaties effective, he allowed European consuls to reside in Zanzibar.
The consuls ensured that both sides obeyed the treaty terms.
They also protected European citizens and traders from mistreatment.
This created a safer trading environment, so trade volume increased.
Answer:C. allowing European consuls to reside in Zanzibar.