Now I can see quite clearly that the big red car has struck the little blue one.
Correct answer: (b) struck the little blue one
Your answer was: [color=red]incorrect
Now I can see quite clearly that the big red car has stricken the little blue one.
[size=200]_________________________[/size]
Stricken and struck are both past participles of the verb to strike.
We use [color=blue]stricken if we want to describe some sort of disease or malady:
BTW, stricken is the past participle of strike (along with struck). (take a look at this to make sure thefreedictionary.com/stricken)
although it seems that noone uses it this way nowadays:)