Express .333 as a fraction in the lowest terms

a. 2/3
b. 1/3
c. 3/1000
d. 3/100

I thought 333/1000 was the lowest term, but of these answers all I can even come up with is if you round 333/1000 can be close to 1/3. 333 plus 333 plus 333. What do you think it is?