Step 1: Use the ratio of price to face value:
A debenture of Rs. 100 issued at 10% discount is sold for Rs. 90. So Rs. 90 of the debt is settled for every Rs. 100 of face value. The face value needed is \[ 99{,}000 \times \frac{100}{90} = 1{,}10{,}000 \]
Step 2: Discount is the gap:
The company records debentures at face value, but the debt settled is only Rs. 99,000. The gap is Rs. 11,000, which is 10% of Rs. 1,10,000. This gap is booked as Discount on Issue of Debentures, a debit balance.
Step 3: Balance the entry:
Debit side: P Ltd. 99,000 plus Discount 11,000 = 1,10,000. Credit side: 12% Debentures 1,10,000. Both sides are equal, so the entry balances.
Step 4: Eliminate wrong entries:
An issue of debentures always credits the Debentures account, so options 3 and 4, which debit it, are wrong. Option 1 ignores the discount and shows Rs. 1,10,000 owed to P Ltd., so it is wrong too.
Final Answer:
Option 2 shows the correct entry.
\[\boxed{\text{Option 2}}\]