C). Principle of lateral continuity.
Hope this helps. :)
I believe the answer is: No, this does not need to be reported because it was assessed by the researcher as unrelated to the research study.
uanticiapted problem refers to the unexpected event that happen to the subject which is caused by the subject's involvement with the study. (This usually covers all form of physical harm and psychological damage that occurs because of the method of study or the substance that given to them during the study)
The correct answer is - erosion.
The sites of the major monuments over time show signs of erosion. As all these sites are made out of natural materials they are not prone to the effects of the erosion. Little by little, over time, they have small parts of them removed with this natural process, thus changing their initial forma and shape, but also threatening to totally destroy them. The erosion has increased in the past century because of the acid rains as they have very high corrosive power.
Because of this, lot of sites of major monuments have been restored, new layers are added, for both making them look as they initially did, and for bigger protection of the natural elements.