Step 1: Write the formal definition:
Fiscal Deficit = Total Expenditure − (Revenue Receipts + Non-debt Capital Receipts).
Step 2: Interpret the gap:
Since non-debt receipts exclude any money raised through loans, whatever expenditure is left uncovered after this subtraction must be financed by borrowing — that is the essential meaning of the fiscal deficit figure.
Step 3: Eliminate the distractors:
Tax shortfalls and disinvestment shortfalls are just individual line items within receipts, not the definition of the deficit itself.
Final Answer:
Option D, borrowing.