In \[S=a+bt+c{{t}^{2}}\]. \[S\] is measured in metres and \[t\] in seconds. The unit of \[c\] is [MP PMT 1993]

• A. None
• B. \[m\]
• C. \[m{{s}^{-1}}\]
• D. \[m{{s}^{-2}}\]