Why does he ask jefferson to do this

hello there i like to you tell question but what is the question i do not understand what why does he asked jefferson to do this if there is more to the answer tell me not to be rude or anything

d) a constitutional amendment

the answer to your question is a. the salt plains

in 1811, he led an expedition, known as the george c. sibley expedition, to improve relations with the pawnee and kansa tribes, and also to locate the rumored jefferson's salt mountain