Walker, who knew nothing about horses, inherited Aberlone, a thoroughbred colt whose disagreeable behavior made him a pest around the barn. Walker sold the colt for $1,500 to Sherwood, an experienced racehorse-trainer who knew of Walker's ignorance about horses. At the time of sale, Walker said to Sherwood, "I hate to say it, but this horse is said to Sherwood, "I hate to say it, but this horse is bad-tempered and nothing special." For this question only, assume that soon after the sale, Aberlone won three races and earned $400,000 for Sherwood. Which of the following additional facts, if established by Walker, would best support his chance of obtaining rescission of the sale to Sherwood? 
Walker did not know until after the sale that Sherwood was an experienced racehorse-trainer. At a pre-sale exercise session of which Sherwood knew that Walker was not aware, Sherwood clocked Aberlone in record-setting time, far surpassing any previous performance.  Aberlone was the only thoroughbred that Walker owned, and Walker did not know how to evaluate young and untested racehorses.  At the time of the sale, Walker was angry and upset over an incident in which Aberlone had reared and thrown a rider. 