Transcription is the transfer of genetic information from DNA to RNA, and it happens in the nucleus. We can automatically rule out B. B is incorrect because it doesn't make sense; how can a process stop before it even begins?
A. I believe this is incorrect because mRNA is involved when the genetic information needs to leave the nucleus. mRNA would take it to a ribosome outside of a nucleus. Since transcription happens in the nucleus, mRNA is irrelevant before it starts.
C. This doesn't really make sense. mRNA carries information from the DNA, but not vice versa (in these early stages).
D. This would make the most sense, since RNA polymerase needs to attach to the promoter on the strand before transcription can begin.
The best possible way to study how tigers interact with each other in their habitats would be to use a naturalistic observation. This type of observation focuses on observing the main subject of the study in it's natural environment without interfering in any sort of way. This allows the scientists to observe exactly how the tigers interact when there are no humans around.