As per the provisions of the Industrial Disputes Act, 1947, 'Lay-off' means the failure, refusal or inability of an employer to give employment to a workman whose name is borne on the master rolls of his industrial establishment and who has not been retrenched on account of

According to Section 2(kkk) of the Industrial Disputes Act, 1947, "lay-off" refers to the failure, refusal, or inability of an employer to provide work to a workman whose name is on the muster rolls (referred to as "master rolls" in the question) and who has not been retrenched.

This inability must arise due to specific reasons mentioned in the Act, which include:

• Shortage of coal, power, or raw materials.
• Accumulation of stocks.
• Breakdown of machinery.
• Natural calamity or any other connected reason.

Since options A, B, and C all represent valid statutory grounds for a lay-off under the Act, the correct answer is All of the above. A lay-off is essentially a temporary suspension of work, distinct from retrenchment, which implies a permanent termination of the service contract.