Final answer:
The answer to 'How long have you lived at your present address?' is 'duration', which is a quantitative continuous variable as it can take on any value in a range and is measured in units of time.
Step-by-step explanation:
The question 'How long have you lived at your present address?' asks for information about a span of time. The correct response from the given options would be 'd) duration' as it specifically refers to the length of time someone has been in a location.
Now, addressing the type of data that duration represents, duration (amount of time) is a quantitative continuous variable. This is because it can be measured along a continuum and does not take on just discrete values; duration can be measured to whatever level of precision is desired (e.g., years, days, seconds, etc.).
Example:
In the context of the Drake Equation to estimate the number of communicating extraterrestrial civilizations in our galaxy, the term 'L' represents the lifetime of a civilization. If we assume this stage lasts only one century, we are using a continuous quantitative measure to quantify a length of time in years.