Which of the following alkyl groups is more powerful electron donating group when they are attached to unsaturated carbon

Which of the following alkyl groups is more powerful electron donating

1.	Which of the following alkyl groups is more powerful electron donating group when they are attached to unsaturated carbon
Answer» `-CH(CH_(3))_(2)` `-CH(CH_(3))C_(2)H_(5)` `-CH_(3)` `-CH(CH_(3))_(3)` SOLUTION :Due to more number of hyper conjugation STRUCTURE.