The first decision for most tenants living in a building undergoing being converted to cooperative ownership is if to sign a no-buy pledge with the other tenants.

a) being converted to cooperative ownership is if to sign
b) being converted to cooperative ownership is whether they should be signing
c) being converted to cooperative ownership is whether or not they sign
d) conversion to cooperative ownership is if to sign
e) conversion to cooperative ownership is whether to sign

In A,B,and C, why is "being converted" wrong? I know that it is wordy and awkward. But, please be more specific.
In C, is "whether or not they sign" wrong?

OA is __E__.