A ‘B’ lymphocyte demonstrates ‘B cell receptors’ on its surface. These receptors have ‘variable’ regions which match the variable regions of the antibodies released by the plasma cell (formed by the...

A ‘B’ lymphocyte demonstrates ‘B cell receptors’ on its surface. These receptors have ‘variable’ regions which match the variable regions of the antibodies released by the plasma cell (formed by the activated B lymphocyte). Which of the following types of antibodies forms these ‘B cell receptors’ ?