Calculate he value of time constant for a sphere for following properties: d=1mm k=35 W/m-K p = 8500 kg/m³ C₂ = 320 J/kg K Convection heat transfer coefficient is h=210 W/m²K. (A)5.16 s (B) 0.568 s (C) 2.158 s (D) 3.75 s