What is a dolmen?
a. a megalithic tomb chamber built with the post-and-lintel method
b. a large stone construction
c. a tomb chamber covered with smaller rocks and dirt

C. a megalithic tomb chamber built with the post-and-lintel method

Explanation:

A dolmen is usually consisting of two or more vertical megaliths supporting a large flat horizontal capstone or "table" (post-and-lintel construction).

you didnt add any sort of groups or any options, you can edit it and then people can try to answer now its kinda hard.

hope this gives you a heads up why you arent answered. : d

have a great rest of your day!