A Gas Has a Molar Heat Capacity at Constant Volume

Multiple Choice

A gas has a molar heat capacity at constant volume of 28.39 J/mol · K.Assume the equipartition theorem to be valid.How many degrees of freedom (including translational) are there for the molecules of this gas? (the ideal-gas law constant is R = 8.31 J/mol · K)

A) 1
B) 3
C) 4
D) 5
E) 7