A citrus fruit grower receives ₹980 for each crate of lemon shipped and ₹1500 for each crate of oranges shipped. How many crates of oranges did the grower ship last week?
I. Last week the numberof crates of lemon that the grower shipped was 20 more than twice the number of crates of orange shipped.
II. Last week the grower received a total of ₹387000 from the crates of lemon and oranges shipped.

Let's take the number of Lemos crates shipped to be $$L$$ and the number of orange crates shipped to be $$O$$. 

The total revenue would be $$980L + 1500O$$. 
We need to find the value of $$O$$

Taking statement 1 alone:
We get the equation that $$L=2O +20$$
From this additional information alone, we cannot find the value of L or O. 

Taking statement 2 alone:
$$980L + 1500O = 387000$$
This is a linear equation and will have many solutions

Taking both the statements together:
We can substitute the value of L as 2O + 20 in the equation we got from the third equation to get the exact value of L and O

In data sufficiency questions, the purpose is to check for the determination of an absolute answer rather than finding the answer. We can leave the solution at this point and mark the answer. 

The value of L would not be an integer.
Although we get a non-integer value for the number of crates. 
The answer can be determined when both the statements are used together. 

Therefore, Option C is the correct answer.