As the given and answers are all fractions, this is merely a trial-and-error method to simplify and see which answers are equivalent to the given fraction. So let us try with all them:
1.) 2/6 = 1/3 (X) 2.) 1/3 is already simplified and is not equivalent to 2/3. (X) 3.) 8/15 is already simplified and is not equivalent to 2/3. (X) 4.) 10/15 = 2/3 (by dividing 5 from both numerator and denominator)
