dehydration of alcohol order

Consider these two factors -
1 Dehydration of alcohols follows SN1 mechanism through carbocation and more stable carbocation (3⁰ ,2⁰, 1  ⁰) formed is more stable .
2 More substituted alkene is also most stable product (Zaitsev's rule)
Now 3⁰ alcohol will be most reactive because it is 3⁰  and forms most substituted alkene and 1⁰ is least reactive. In 1⁰ pick up the alcohol which gives you least substituted alkene.
Based on these factors predict the right answer.