Q.Wages paid for installation of machinery wrongly debited to wages account is an error of

Debiting installation wages to Wages A/c instead of Machinery A/c is an error of principle — option (b).

What is an error of principle?

• It occurs when a transaction is recorded in violation of an accounting principle — most commonly by mixing up capital and revenue items.
• Wages paid for installation of machinery are a capital expenditure — they add to the cost of bringing the machinery into working condition, so they should be debited to Machinery A/c.
• Debiting them instead to Wages A/c (a revenue expense) wrongly treats a capital item as revenue. This is an error of principle.

Why not the others? …