(a) A leading horse in a race around a turn is entitled to any part of the course; however, when another horse is attempting to pass in a clear opening, the leading horse may not impede the passing horse by crossing over so as to compel the passing horse to shorten its stride. A leading horse in a straightaway race must maintain a course as nearly as possible in the lane in which it starts.(b) A horse may not interfere with or cause another horse to lose stride, lose ground, or lose position in a part of the race where the horse interfered with loses the opportunity to place where the horse might be reasonably expected to finish.(c) The stewards may disqualify a horse who interferes with another horse in violation of this section and may place the horse behind the horse interfered with.(d) The stewards shall display the inquiry sign on the tote board immediately on observing possible interference.