______ party shall notify the other party of the ratification by their respective authorities.
question: I feel 【each】> or = 3 aspects, 【either】=2 aspects, so I think 【either】 is right and 【each】 is wrong! But why is the key opposite?
Here 'Each party shall...' means 'Both parties shall...'. The intended meaning is that both parties must notify the other party.
'Either party' and "shall" are not compatible together.
A sentence like 'Either party may cancel the agreement, thereby making it null and void.' would be correct.