Anange the following alkenes in decreasing order of stability. 

Choose the correct answer from the options given below:

Alkene stability is dictated by the number of $$\alpha$$-hydrogens available for hyperconjugation (more $$\alpha\text{-H}$$ = greater stability) and the degree of substitution.

1. Structure I (Tetra-substituted alkene):
   • It has 4 methyl groups attached to the double bond.
   • Number of $$\alpha$$-hydrogens = $$4 \times 3 = 12\text{ }\alpha\text{-H}$$
   • Status: Most stable.
     $$\text{}$$
2. Structure III (Tri-substituted alkene):
   • It has 3 methyl groups and 1 hydrogen atom attached to the double bond.
   • Number of $$\alpha$$-hydrogens = $$3 \times 3 = 9\text{ }\alpha\text{-H}$$
   • Status: Second most stable.
     $$\text{}$$
3. Structure II and Structure IV (Di-substituted alkenes):
   • Both structures have 2 methyl groups and 2 hydrogen atoms, giving them both $$2 \times 3 = 6\text{ }\alpha\text{-H}$$.
     $$\text{}$$
     Structure II is a trans-alkene (the bulky methyl groups are on opposite sides, minimizing steric hindrance).
     $$\text{}$$
     Structure IV is a cis-alkene (the methyl groups are on the same side, causing steric crowding between them).
     $$\text{}$$
     Because trans-alkenes have less steric strain than cis-alkenes, Structure II is more stable than Structure IV.

Therefore, the correct choice is [C] I > III > II > IV.