Step 1: Recall that communication models differ in element count - Aristotle (3), Berlo's SMCR (4), Shannon-Weaver (5).
Step 2: Leagans' model, built for agricultural extension, is specifically known for its six-component framework.
Step 3: This rules out the 3, 4 and 5-element options, which belong to other theorists.
Step 4: Hence the Leagans model contains 6 elements (Option 1).