The income elasticity of demand for private universities is closest to:

A. 0.5 .

B. 0.8 .

C. 1.3 .

The market demand function for four-year private universities is given by the equation:

\[ Q_{p r}^{d}=84-3.1 P_{p r}+0.8 I+0.9 P_{p u} \]

where \(Q_{p r}^{d}\) is the number of applicants to private universities per year in thousands, \(P_{p r}\) is the average price of private universities (in thousands of USD), \(I\) is the household monthly income (in thousands of USD), and \(P_{p u}\) is the average price of public (government-supported) universities (in thousands of USD). Assume that \(P_{p r}\) is equal to \(38, I\) is equal to 100 , and \(P_{p u}\) is equal to 18.