Final answer:
Based on the evolutionary relationships explained in the provided text, the resulting phylogenetic tree would likely suggest that C. cherries (an angiosperm) and peas (another angiosperm) are each other's closest relatives.
Step-by-step explanation:
In constructing a phylogenetic tree using the given data, one would analyze the shared characteristics among the species mentioned, which includes mosses, ferns, cherries, and peas. Based on the information provided, particularly the context that mosses are an outgroup and noting evolutionary relationships, one might suggest the closest relations among these species. Because ferns and mosses are not closely related despite both lacking seeds, as indicated in the text about 'fern allies', we could surmise that mosses and peas are also not closest relatives.
Considering spermatophytes which include gymnosperms and angiosperms, a separation is made between plants that produce seeds (spermatophytes), like pines and cherries (gymnosperms and angiosperms, respectively), and those that do not, like mosses. Bearing this in mind, cherries and peas (both angiosperms) would likely share a closer relationship to each other than to ferns or gymnosperms like pines. Therefore, the resulting phylogenetic tree would most plausibly suggest that cherries and peas are each other's closest relatives (option C), rather than any of the other pairings provided.