From the following kinetic data given for the reaction of A and B
 

[A]	[B]	Initial rate (mol L-1S-1)
0.01M	0.02M	$2\times {10}^{-4}$
0.02M	0.02M	$4\times {10}^{-4}$
0.02M	0.04M	$8\times {10}^{-4}$

Which of the following observations are correct?

a) is doubled rate of reaction is also doubled. Hence order of reaction with respect A is 1

 b) is doubled rate of reaction is also doubled. Hence order of reaction with respect B is 1 Total order of reaction is 2. If doubled the concentration of A & B rate of reaction increased by 4 times