To determine which species is most closely related to species 4, we usually look for the species that share the most recent common ancestor with species 4 on the phylogenetic tree. However, since I cannot see the specific phylogeny you're referencing, I can only guide you on how to approach the question.
If species 4 and species 5 share a more recent branching point than species 4 does with species 1 or 3, then species 5 would be the answer. Conversely, if species 4 is more closely related to species 1 or 3 based on their branching pattern, then one of those species would be the answer.
If there is ambiguity with the connections, "1 or 3 (Can't tell)" could also be a valid option.
Please review the phylogenetic tree to identify the nearest connections to species 4.