Prerna Exp do have two Rake, one dedicated to run as Prerna Exp, departing on We & Sa from NGP & it may have only 3A not 2A!!
While Su departing Prerna Exp is in RSA with NGP-JP Exp (which do have 2A)!!
So, Prerna which depart on Su do have A1 & B1 while We & Sa departing Prerna do have B1 only!!