An allotrope of carbon which exhibits only two types of C - C bond distance of 143 . 5   pm and 138 . 3   pm , is

Step-by-step solution

In fullerene, each carbon is bonded to three other carbon atoms. Two types of those bonds are of greater single bond character and greater length 143 . 5   pm and one is of greater double bond character and shorter length 138 . 3   pm .