Answer: The correct option is (C)

Step-by-step explanation: Given that Jane has
dozen boxes of envelopes and she ordered
dozen more.
We are to find the total dozen of boxes that Jane will have.
The total dozen of boxes that Jane will have is equal to the sum of dozen of boxes she has now and the dozen of boxes she has ordered.
Therefore, the total dozen of boxes Jane will have is given y

Thus, the total dozen of boxes that Jane will have is

Option (C) is correct.