In the given structure one of the carbon atoms along the double bond has identical group (methyl), hence it cannot show geometrical isomerism. Tautomerism is not possible because of the absence of −CO group. It shows optical isomerism because it has chiral C atom with four differentgroups, H,  CH3,  COOH  and  CH32C=CH.  A compound which consists of at least one asymmetric carbon atom is capable of showing the phenomenon of optical isomerism.