Yep only 2 is needed, however you should be prepared to write with only 1. The question will be worded as either ONLY ONE or ATLEAST ONE or TWO (which is mainly done by schools). 4 is excessively wasteful and is you're better of spending that time concentrating on your core text.Is that four per module? Personally I prepared with only two per essay. The questions will generally ask 'for at least one' so you use two, but sometimes they only ask for one, which in that case you would definitely not use any more. If you were looking to incorporate four into one essay you wouldn't really be analysing the set text properly.