The sum, of the coefficients of the first \( 50 \) terms in the binomial expansion of \( (1-x)^{100} \), is equal to:
\( -\,^{99}C_{49} \)
\( -\,^{101}C_{50} \)
\( ^{101}C_{50} \)
\( ^{99}C_{49} \)