That question doesnt make sense
D because it includes more information than the others and is more professional
The correct answer is D. A the red car was more fast,uses the comparing adverb incorrectly. B the red car was the fastest than the orange car doesn't sound correct and uses it incorrectly as well. C the red car was most fast is as well used incorrectly and sounds incorrect while<span>D.
The red race car was faster than the orange car. makes perfect snese as the comparing adverb is faster and goes together in the sentence because it is comparing the red car and the orange car.
Hope I helped</span>