Step 1: Legal Basis.
Section 52 of the Companies Act, 2013, specifies the permitted uses of the Securities Premium Account. These include: - Issuance of fully paid bonus shares. - Amortization of preliminary expenses, commission, or discount on issue. - Payment of premium on redemption of preference shares or debentures. - Buy-back of the company's own shares.
Step 2: Evaluation of Options.
(A) Issuance of partly paid bonus shares → Invalid (only fully paid bonus shares are legally permissible).
(B) Buy-back of own shares → Valid.
(C) Write-off of expenses, commission, or discount → Valid.
(D) Payment of premium on redemption → Valid.
Step 3: Determination.
Accordingly, the valid options are (B), (C), and (D).
Final Determination: \[\boxed{(B), (C) \text{ and } (D) \text{ only}}\]