step1

given information

Alexis advertised that 75 percent of thew cars that she sold were red

probablity that cars were red = 75/100 =0.75

probablity that cars were not red = 1- 0.75 = 0.25 

step2   now  let   see   Which of these could not be used to stimulate the number of not red cars that Alexis sold 

a)

Toss a fair coin-once

probablity of head = 1/2 =0.5

proablity of tail = 1/2=0.5

b)

Spin a spinner with 4 equally-sized sections.

prabablity will be 1/4 =0.25

c)

Draw a card from a deck of cards numbered 1 thru 24.

again here 

probablity will be = 1/4= 0.25

d)

Use a random number generator to generate the digits 1 thru 8.

proabablity of using random number  is = 2/8 = 0.25

  we see above all probablity equals to 0.25  except  first case  a

so   tossing  fair coin once could not be used to stimulate the number of not red cars that Alexis sold