C is the current average.
E1 C still has 2+ months bonus because management trying to let the E1s hit 100k annual.
E2 C is the worst as this is the majority pool of people, lesser bonus is given (usually 1month or even lower) to let you self resign (HR call self cleanse)
E3 ( and above) C has more bonus, usually 2 or above, higher grade even more, in order to retain experienced staff.