which signalling pathway is involved in cancer?
The answer is b, as the mutation constantly activates the RAS protein. RAS is part of the MAP-Kinase pathway, constant signaling of it permanently activates this pathway and leads to changes in gene expression. See the image below:



If you are interested in more details, have a look at these papers:


RAS oncogenes: weaving a tumorigenic web
RAS mutations and oncogenesis: not all RAS mutations are created
equally