An element which is tetravalent and forms the basis of organic chemistry is:

Concept: Organic Chemistry is the study of hydrocarbons.
Hydrocarbons are the vast class of compounds having hydrogens and carbons. From the given options, the only tetravalent element is carbon. Carbon is a group 14 element with electronic configuration 2, 4. By losing or accepting 4 electrons carbon attains octet valence. Thus the basic tetravalent element which is the base of organic chemistry is Carbon.
Oxidation is more significant in . It may combine to produce double and triple bonds, among other types of bonds. The most crucial characteristic is catenation. The process of joining atoms of the same element in a series is known as catenation. Among group 14, the nonmetals include carbon and silicon. The majority of non-living objects, such as soil, rocks, and hills, all contain carbon.
Hence, the correct answer is option 1.