I don't see any options, but once you factor x^2-5x+4, you get (x−1)(x−4)! So it's one or the other :)
D) 4/5
Because the lace is 3.2 ydlong, so 3.2÷4=4/5
He is incorrect because if the ratio is that for every 6 ft on the model is 8 feet in real life, he already exceeded his Kennedy's height by 2.