Amitriptyline, sold under the brand name Elavil is a tricyclic antidepressant. The flowchart below outlines its chemical synthesis.

Select the correct statement(s) :

 MgI is a possible Grignard reagent in step-1 followed by acid workup

Step-2 involves the formation of a highly stable carbocation intermediate

a primary carbocation is not formed as an intermediate at any point during the drug making

diethyl amine attacks in an  $S_{N_2}$ manner in step-3