Both parents-petitioners file separate i130 applications for one adult Child?

[Azpqm]

Background situation is : birth country of the unmarried adult beneficiary child gives >5 years waiting period to priority date.

A)What is the advantage of having both US citizen parents (married to each other ) EACH file separate i-130 forms for the SAME adult-unmarried-beneficiary child?
B)Is it necessary in case of unforeseen circumstances? C) Would the USCIS typically reject ONE OF THE TWO petitioners’ appplications at the time of file-acceptance/file-establishment or they won’t reject one of the two until close to the time to Priority Date?

[newacct]

They won't reject either of them -- it's not a conflict to be the beneficiary of multiple petitions. The only advantage of both parents petitioning is if one of the parents die, and thus that parent's petition becomes void, the other parent's petition is still progressing.