Pre-thinking
Sum of the five numbers are 16 * 5 = 80.
(1) Only
It is possible that the sum of the two largest numbers in the set greater than 34. Say, 20.01+19 = 39.01. The other three numbers add up to 80-39.01=40.99. So they can be 13, 13.99, 14.
Now, is it possible for the sum of the two largest numbers smaller than or equal to 34? Let's try 20.01+13.99=34. The other three numbers add up to 80-34 = 46. But 46/3>15, which means at least one number should be larger than 15, which is > 13.99. So, it is
not possible for the sum of the two
largest numbers to be smaller than or equal to 34.
We can definitely answer the question. The answer is "Yes". (1) is sufficient.
(2) Only
In 16, 16, 16, 16, 16, the sum of the two largest numbers in the set is 32 < 34.
In 14, 15, 16, 17, 18, the sum of the two largest numbers in the set is 35 > 34. (The sum of the two largest numbers can be much higher: 100, 1000, 100000, etc.)
Not sufficient.
The answer is
(A).