A plastic sphere floats in a fluid with $40\mathrm{.}0$ percent of its volume submerged. If the density of the plastic ball is $500k\frac{g}{m^3}.$ The density of the fluid is

a$)1250k\frac{g}{m^3}$

b$)1000k\frac{g}{m^3}$

c$)40k\frac{g}{m^3}$

d$)1500k\frac{g}{m^3}.$