Which of the following is not a requirement that must be met before a group files a consolidated return?

a$.$ None of the corporations can be ineligible under the Code to file on a consolidated basis with the others.

b$.$ The group members must share the same inventory accounting method, $($e$.$g$.,$ they all must use FIFO$).$

c$.$ All of the corporations must be members of an affiliated group.

d$.$ The group members must share a common tax year end.