Unlike human runners, who broke the four-minute mile in 1954 and they consistently recorded faster times ever since, horses in classic races such as the Kentucky Derby have had winning times with little improvement: Secretariat's world-record-breaking Derby tine of 1:59 2/5, for example, was set in 1973 and remained unsurpassed more than a quarter of a century later.

(A) they consistently recorded faster times ever since, horses in classic races such as the Kentucky Derby have had winning times with little improvement

(B) they have consistently recorded faster times ever since, those of horses in classic races such as the Kentucky Derby have shown little improvement in winning times

(C) have consistently recorded faster times ever since, horses in classic races such as the Kentucky Derby have shown little improvement in winning times

(D) have consistently recorded faster times ever since, in those of classic races such as the Kentucky Derby, horses have had winning times with little improvement

(E) consistently recorded faster times ever since, those of horses in classic races such as the Kentucky Derby have shown little improvement in winning times

OA C

Source: GMAT Prep