A solution of organic substance is to be concentrated from $18$ to $42wt\%$ solids in a singleeffect evaporator. The feed enters at ambient temperature $(28C),$ with negligible boiling point rise. Saturated steam is available at $1\mathrm{.}8$barg. The evaporator is designed to vaporize $6400\frac{kg}{h}$ during normal operation. Which of the following combinations of HTC $(\frac{W}{m^2}(K))$ and heating surface $(m^2)$ is possible?