r and r? denote the angles inside an equilateral prism, as usual, in degrees. Consider that during some time interval from \[t=0\] to \[t=t,\,r'\] varies with time as \[r'=10+{{t}^{2}}.\] During this time r will vary as: (Assume that r and r? are in degree):

• A. \[50-{{t}^{2}}\]
• B. \[50+{{t}^{2}}\]
• C. \[60-{{t}^{2}}\]
• D. \[60+{{t}^{2}}\]