SNOBOL ("StriNg Oriented and symBOlic Language") is a series of computer programming languages developed between 1962 and 1967 at AT&T Bell Laboratories by David J. Farber, Ralph E. Griswold and Ivan P. Polonsky, culminating in SNOBOL4. It was one of a number of text-string-oriented languages developed during the 1950s and 1960s; others included COMIT and TRAC.
SNOBOL4 was the first computer programming language developed by AT&T Bell Laboratories.
Since the context states that SNOBOL was a SERIES of languages that CULMINATED in SNOBOL4 over a period of several years, then my statement that SNOBOL4 came first was definitely wrong. Not sure why it was difficult for the system but perhaps it can't determine the meaning of series or culminated.