Solution:
concept - Carbon exists in more than one form and these forms are graphite, diamond, and fullerene. Carbon is able to show allotropes due to its property of catenation and pΠ-pΠ bond formation.Thus, carbon shows allotropy and exists in 3 forms- diamond, graphite, and fullerene.
Coal and coke are amorphous forms of carbon because they lack long-range order but they are not allotropes as they do not have pure carbon content.
Among the allotropes of carbon, diamond is a crystalline substance used in making jewellery. Graphite is also a crystalline allotrope of carbon.
Thus, the correct options are 3 and 4.
