How much precipitation does Springfield need this month to attain its

St1: Over the last 11 months, the city has averaged 3 inches of precipitation per month.
This statement is sufficient if we assume that "this month" refers to the final month of the year.
But, if its not the final month of the year then the average precipitation is dependent on the months remaining in the year
St1 is not sufficient

St2: Springfield has accumulated 94.3% of its mean annual precipitation during the last 11 months.
This statement is similar to statement 1. It provides total precipitation value for the previous 11 months as (0.943)*(35). This statement is sufficient if the month refers to the final month of the year. If its not the final month then its not sufficient.

Combining St1 and St2, we still get the value for the previous 11 months. But we do not have any information to suggest that the previous 11 months refers to the first 11 months of the year.

Answer: E