“Either of these two roads ___ to the post office.”

"In “Either of these two roads leads to the post office” “leads” is the singular verb agreeing with the singular subject “either.” Subject-verb agreement is a cornerstone of English grammar ensuring sentence clarity and correctness. This rule is vital in formal writing and speech preventing errors that could confuse meaning. Proper verb choice enhances communication particularly in instructional or directional contexts where precision is necessary for effective guidance or information delivery."