Yes you can activate without using internet, given below the steps for offline activation:
STEP 1. Enter the Serial Number and click on Submit.
STEP 2. Choose your standard and click on Go to step 3.
STEP 3. Call the support center and give them the code displayed in red and click on Go to step
STEP 4. Enter the activation code given to you by the support center and click on Activate serial key button to activate your serial key.