The optimization problem below indicates a utility maximization problem for

Emma, where $x1$ and $x2$ denote her demand for good $1$ and $2,$ respectively.

Which $of$ the following statements $is$ not true?

$ma{x}_{x_1,x_2}0x_1^2{x}_2^3,$ subject $to2x_1+x_{2}10$

Emma's utility function $is$ not concave but quasiconcave.

$At(x1,x2)=(1,2)x1,x2=(2,6).$

The marginal utility $ofan$ extra dollar $to$ Emma $is432$ utils.

When her income doubles, demand for good $1$ and $2$ both increase.