Hello!
A) The trails were used to protect the cattle from severe weather.
(Nope! Although some trails did help, this was not a main reason for the creation.)
B) Men including Charles Goodnight built the trails in order to move the cattle to the stockyards.
(This seems like the best option! Charles Goodnight did build trails to move cattle towards the stockyards)
C)Tourists used the trails, bringing additional revenue to the ranchers.
(Nope! These trails were used for cattle, and cattle alone.)
D) Ranchers wanted to move their herds to better grazing land in the West.
(Nope! These trails were used to bring cattle towards the higher-paying markets in the North-East.)
I hope this helps! :)