The correct answer is "built."
To construct something is to "build" something, but to deconstruct something is to take down or destroy something.
The prefix "de" means off, away from, or not something, for example the word deactivate, activate means to make something active or operative; therefore, deactivate means to make something not active.
Therefore, built is the opposite of deconstructed.
I hope this helps you. :)