Straight-line depreciation on total historical cost after trade discount Steps:

• Calculate net purchase price: $80,000 × 90$72,000
• Add delivery and installation: $72,000 +$2,000 + $1,000 =$75,000 total cost
• Subtract residual value: $75,000 -$5,000 = $70,000 depreciable amount
• Divide by useful life: $70,000 ÷ 5 years =$14,000 annual depreciation Why B is correct:
• Straight-line method allocates (historical cost - residual value) evenly over useful life, per accounting standards like IAS 16. Why the others are wrong:
• A: Ignores delivery and installation costs, understating total cost at $72,000 before residual adjustment.
• C: Applies discount incorrectly to total costs including delivery/installation, yielding $74,100 depreciable amount.
• D: Treats $80,000 as net cost without applying the 10% discount, overstating purchase price.

Final answer: B