Question

The storm made a tree fall across the road making the main route into the village _____.

undetectable
unacceptable
inaccessible
ineffable

Answer 1

inaccessible. the prefix "in-" means not, so when you put them together it means not accessible so the answer is INACCESSIBLE 

Answer 2

inaccessible, since accessible means to access something and the prefix "in" means not able to