Answer:
B- weight 135 pounds
Explanation:
Pony Express is a mail delivery system in the mid 19th century in between states as a means of delivering mail and information quicker. The usual relay of messages had been done by the overland stagecoaches that sometimes take almost a month. But with the tensions starting with the Civil War, the need to relay messages quicker was imperative. So, thus began the Pony express. They employ young lightweight riders who will be able to travel long distances in a shorter duration in faster speed. They switched horses every 10-15 miles and transferring the cargo to the next rider after every 75-100 miles. From the given passage, we can deduce that a pony express rider has to be around 135 pounds in weight, the lighter the weight, the easier the load on the horse will be.
