Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature \[{{T}_{0}},\] While Box B contains one mole of helium at temperature (7/3) \[{{T}_{0}}\]. The boxes are then put into thermal contact with each other and heat flows between them until the gases reach a common final temperature (Ignore the heat capacity of boxes). Then, the final temperature of the gases, \[{{T}_{f}},\] in term of \[{{T}_{0}}\] is

• A. \[{{T}_{f}}=\frac{7}{3}{{T}_{0}}\]
• B. \[{{T}_{f}}=\frac{3}{2}{{T}_{0}}\]
• C. \[{{T}_{f}}=\frac{5}{2}{{T}_{0}}\]
• D. \[{{T}_{f}}=\frac{3}{7}{{T}_{0}}\]