In which of the LCR circuit the charge will decay faster?
You could make an extreme case examination. If Cc is a lot smaller than C you could argue that Cc (as an example) could be zero and, in this extreme case, circuit (B) will continue to resonate until the end of time.

Another way of looking at it is by examing the AC voltage across the resistor in (B) - it can only ever be lower in amplitude compared to voltage across the resistor in circuit (A) therefore, the circuit losses in (B) have to be lower and therefore circuit (B) takes longer to decay.

Now what if Cc were infinite? This would turn circuit (B) into circuit (A) therefore, by inspection, for any reasonable value of Cc, the voltage across R will be less than it would be when Cc is infinite. There is only one conclusion here and that is this: circuit (B) takes longer to decay than circuit (A).