Which of the Following Is True About the Cell-Wall-Less Archaeal $\degree$

Which of the following is true about the cell-wall-less archaeal genus Thermoplasma?

A) They are spherical at temperatures below 59 $\degree$ C.
B) They are filamentous at temperatures at 59 $\degree$ C and higher.
C) They are non-motile.
D) They are spherical at temperatures below 59 $\degree$ C and they are filamentous at temperatures at 59 $\degree$ C and higher.
ASM