Question

True breeding whilte flowering plants are crossed to true breeding red flowering plants. the offspring are red flowered. when these flowers are self crossed, the resultant offspring are 92 red, 57 pink and 12 white flowered plants. which of the folloeing pathways is most likely the cause of this?

A. white --A-> pink--B-->red

B. pink --A-->pink--B-->red

C. red <--A--white--B-->red

D. white --A--> pink white --B-->pink both genes producing pink together give red (this is the correct answer) but why>?

can someone explain what are pathways how do i tackle a question like this? i know the right answer but cannot understand why this is a practice quetsion and nothing in my book explains how to do this