Quadratic equations

Indicate which of the following equations are quadratic:

a) $x^2 - \frac{1}{5} = 0$

b) $7x - \frac{19}{6} = 0$

c) $\frac{5}{3}x^2 +13x = 0$

d) $2x + \frac{11}{4} = 0$

e) $\frac{3}{2}x^2 - 7 = 0$