设 S=113+123+133+⋯+1993S = \frac{1}{{1}^{3}} + \frac{1}{{2}^{3}} + \frac{1}{{3}^{3}} + \cdots + \frac{1}{{99}^{3}}S=131+231+331+⋯+9931 ,则 4S{4S}4S 的整数部分等于 ( )A. 4B. 5C. 6D. 7