B.
For those that could not write (So most), they carried a seal around either on a necklace or otherwise that they could use to stamp with ink to signify 'signing' something.
To hold off till they were all in one place
The correct answer is rice. That means that they produce all of the rice found in the country and there is no need for any rice to be imported. Even if there was nothing else and sanctions were imposed, they would still have rice and the people could eat it.
Their geography made growing crops difficult. The land was mountainous. They were however, known for growing grapes and olives.
Answer:
ali was the first caliph of the prophet