Dependent on how long the checklist responses are you can also use drop down content control which can be found under the Developer Tab.

If this is not showing go to File Tab|Options|Customize Ribbon. In the Customize The Ribbon|Main Tabs dialog box this will show you the Tabs available to you, check the Developer Tab box and click OK. This will then show as a Tab on the Ribbon.

It might be an idea to upload your document and the checklist to this thread as sometimes it's hard to give advice blind.

Good Luck