The decreasing order of reactivity of the following alkenes towards HBr addition is:
\(\text{CH}_3-\text{CH}=\text{CH}_2 \, (\text{I}), \quad \text{CF}_3-\text{CH}=\text{CH}_2 \, (\text{II}), \quad \text{MeOCH}=\text{CH}_2 \, (\text{III}),\) 
,
\((\text{IV}) \)