I had seen a perfect ___ for my project.

The correct choice in this context is "site," which refers to a specific location or place suitable for a project. In the sentence "I had seen a perfect ___ for my project," the word "site" aligns perfectly because it denotes an appropriate area or venue where the project could be executed or developed.

The meaning of the other options does not fit this context. "Sight" typically pertains to vision or the ability to see, which has no relevance when describing a location for a project. "Cite" is a verb that means to quote or reference a source, which also does not apply when discussing a suitable place. The word "zite" does not exist in standard English usage and therefore does not provide a valid choice. Thus, "site" is the only word that appropriately completes the sentence in a meaningful way.