Who was the biggest "Weekend Update" host during that time period?
Python 2, 291 bytes



def f(b,e):
 s=''.join('A AB BC BCD BD BDE EFGH GHJ J JK KL L L L L L LM M M MN N N N O O OPQ PQ PQ PQ PQR QR QRS RS RS S S S S ST STUV UV UV UV'.split()[b-1975:e-1974]);C=s.count;return''.join({'CJDBCGBMCBCDKNCJTASCCMCCAMRMDGEHGMNMQFFPMSJC'[ord(h)-65::22]for h in s if C(h)==max(map(C,s))})


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