217 cm² (option C)
Explanation:[tex]Surface\text{ area = }\pi r^{2}\text{ + }\pi rl[/tex][tex]\begin{gathered} \text{diameter = 6 cm} \\ \text{radius = diameter/2 = 6cm/2} \\ r\text{ = radius = 3cm} \\ l\text{ = 20cm} \\ \pi\text{ = 3.14} \end{gathered}[/tex][tex]\begin{gathered} \text{Surface area of cone = (}3.14\text{ }\times3^2)+^{}\text{ (3.14 }\times\text{ 3 }\times\text{ 20)} \\ \text{Surface area of cone = 28.26 + 188.4} \\ \text{Surface area of cone = }216.66 \end{gathered}[/tex]To the nearest square centimeter, surface area = 217 cm² (option C)