The Laplace Transform of unit step function and ramp functions respectively are

• A.  \[\frac{1}{{{s}^{2}}},\,\,\frac{1}{s}\]             
• B.  \[\frac{1}{s},\,\,\frac{1}{{{s}^{2}}}\]
• C.  \[\frac{1}{s},\,\,\frac{1}{{{s}^{3}}}\]             
• D.  \[\frac{1}{{{s}^{3}}},\,\,\frac{1}{s}\]