The information in the question is pretty insufficient - it might make sense within your course and what you have been told, or the preceding questions, which we do not know.
My best guess for what the first question could
mean(!) would be "The flower colour can be influenced by external conditions (temperature, nutrients, minerals or something). The mechanism of this influence has been shown to be that the influencing factor somehow causes degradation of transcripts of a particular gene." I have to presume that it is meant that the effect is not seen until the second generation, and that the treatment with the factor continues then.
What then is described sounds like what is known as mosaicsm. When a character depends on transcripts expressed in early development, if transcription is interfered with, the transcripts can be present in some cells and not others, making a "mosaic" of cells in the organism, example IIRC tortoiseshell cats.
On the face of it I would say it has to be C not D, because
some of the plant is red. But maybe D is just possible, through cytoplasmic carry-over of transcripts. I have never heard of such phenomenon, but that is not a strong argument, and if it is thinkable it probably happens somewhere.
I would say C and the others not, because (cheating) there is nothing in the premisses to implicate them. I suspect it would be clearer if we had questions 1 and 2.