[JEE Advanced 2005] source incomplete the value of sum a binomial coefficient sum not captured in the

[Source incomplete] The value of $\sum\,(\dots)$ (a binomial-coefficient sum, not captured in the source) is

(a) $\binom{30}{10}$
(b) $\binom{30}{15}$
(c) $\binom{60}{30}$
(d) $\binom{31}{10}$