Answer:
The scientific claim that is most consistent with the findings in the question given is that: histone methylation opens up chromatin at gene R, so transcription factors can bind to DNA more easily.
Step-by-step explanation:
The transcription of the R gene decreases when histone methyltransferase is inhibited, this proves that histone methylation increases the transcription of the R gene.
When the gene is in the condensed state, RNA polymerase can no longer gain access to the region so as to transcribe the R gene. Thus, in order for the gene to be transcribed, the gene has to be in the open (euchromatin) state.
Histone methylation makes the gene in the euchromatin state.
Therefore, the scientific claim that is most consistent with the findings in the question given is that: histone methylation opens up chromatin at gene R, so transcription factors can bind to DNA more easily.