The coefficient of \( x^{48} \) in \( (1 + x) + 2(1 + x)^{2} + 3(1 + x)^{3} + \ldots + 100(1 + x)^{100} \) is:
\( {}^{100}C_{50} + {}^{101}C_{49} \)
\( 100 \cdot {}^{100}C_{49} - {}^{100}C_{50} \)
\( 100 \cdot {}^{100}C_{49} - {}^{100}C_{48} \)
\( 100 \cdot {}^{101}C_{49} - {}^{101}C_{50} \)