If you want only one answer from each person, ensure that the options are mutually exclusive. For example:
In which of the following do you live?
A house
An apartment
The suburbs
This question ignores the possibility of someone living in a house or an apartment in the suburbs.
And there's this:
Make sure you include all the relevant alternatives as answer choices. Leaving out a choice can give misleading results. For example, a number of recent polls that ask Americans if they support the death penalty "Yes" or "No" have found 70-75% of the respondents choosing �Yes.� Polls that offer the choice between the death penalty and life in prison without the possibility of parole show support for the death penalty at about 50-60%. Polls that offer the alternatives of the death penalty or life in prison without the possibility of parole, with the inmates working in prison to pay restitution to their victims’ families have found support for the death penalty closer to 30%.
(Via All This ChittahChattah)