D is the correct answer.
When you add fractions, the answer is always rational.
1/5+-2/3= 3/15-10/15 = -7/15
A B and C are all irrational because they are nonterminating and nonrepeating decimals, which cannot be represented as a ratio of two integers. When you add a fraction to an irrational number, the result is still irrational.
