Classic Data Sufficiency setup. Let's call the number of products on list 1 as "a" and list 2 as "b."
The question tells us: a * b = 42. We need to find "a."
Factorizations of 42 to consider: 1*42, 2*21, 3*14, 6*7. Without anything else, we can't determine a.
Statement (1): a > b. This narrows things down to (a, b) being (7,6), (14,3), (21,2), or (42,1). Multiple options, so not sufficient.
Statement (2): a + b = 13. Combined with a * b = 42, we get a quadratic: n^2 - 13n + 42 = 0, which factors as (n-6)(n-7) = 0. So a = 6 or a = 7. Still two options -- we don't know which list is list 1 and which is list 2. Not sufficient alone.
(1) + (2) together: a + b = 13, a * b = 42, and a > b. From statement 2 we know {a, b} = {6, 7}. Since a > b, we get a = 7. Sufficient.
Answer: C.
The trap in this one is thinking statement 2 alone is sufficient because it pins down the two numbers as 6 and 7. But "sufficient" for Data Sufficiency means we can determine a unique value for list 1 specifically -- and statement 2 alone doesn't tell us which of the two lists is the bigger one.