In a cross section of a vertebrate axon, longitudinally organized cytoskeletal proteins can be seen as dots, as shown in the schematic drawing below. What type of filaments do these dots represent? 
A) Microtubules and microfilaments
B) Microtubules and vimentins
C) Microtubules and neurofilaments
D) Microtubules and keratins
E) Microtubules and septins