The Central Government shall remove a member from Board in certain cases. Which of the following is not a valid ground?

Section 6 of SEBI Act - Removal of member from office - The Central Government shall remove a member from office if he— (a) is, or at any time has been, adjudicated as insolvent; (b) is of unsound mind and stands so declared by a competent court; (c) has been convicted of an offence which, in the opinion of the Central Government, involves a moral turpitude; (e) has, in the opinion of the Central Government, so abused his position as to render his continuation in office detrimental to the public interest: Provided that no member shall be removed under this clause unless he has been given a reasonable opportunity of being heard in the matter.