The sets $S subscript 1 comma S subscript 2 comma S subscript 3 comma horizontal ellipsis horizontal ellipsis$ are given by $S subscript 1 equals open parentheses 2 over 1 close parentheses comma S subscript 2 equals open parentheses 3 over 2 comma 7 over 2 close parentheses comma S subscript 3 equals open parentheses 4 over 3 comma 9 over 3 comma 14 over 3 close parentheses S subscript 4 equals open parentheses 5 over 4 comma 11 over 4 comma 17 over 4 comma 23 over 4 close parentheses horizontal ellipsis horizontal ellipsis$ then the sum of numbers in the set $S subscript 20$ is :

320
235
230
325