Hello. You forgot to show the answer options. The options are:
What are three landmarks in Washington, D.C.?
Where is Washington, D.C.?
How big is Washington, D.C.?
What does D.C. mean?
How was the White House constructed?
Answer:
What are three landmarks in Washington, D.C.?
Step-by-step explanation:
Open-ended research question are questions that allow for free answers, that is, the answers can be answered with something other than "yes" and "no" leaving the person who is going to answer free to use the words they want. While all of the above can be considered an open-ended research question, only the first option encompasses the three items requested in the question, whether directly such as "Washington, D.C." and "landmarks," as indirectly, as "the White House."