The principle that specified that the amount, when and how to pay tax should be made known to tax payer is known as

1. Analyze the question The question asks for the canon (principle) of taxation which says a taxpayer must know the amount to pay, when to pay, and how to pay.

2. Explain the concept Adam Smith's four canons of taxation are:

• Equity (Justice): Tax should be based on ability to pay.
• Certainty: The amount, time, and manner of payment should be clear to the taxpayer and not arbitrary.
• Convenience: Tax should be collected at a time and in a manner convenient to the taxpayer, such as deducting PAYE from salary.
• Economy: The cost of collecting the tax should be low compared with the revenue it raises.

Simplicity is often added by modern writers. It means the tax system should be easy to understand and not complicated.

3. Step-by-step solution

• The key words are "amount, when and how to pay... made known to the taxpayer." This is about clarity and the absence of arbitrariness, which is certainty.
• Economy is about low collection costs, so it is not the answer.
• Convenience is about ease of payment, such as timing and method suited to the taxpayer. It is related, but it does not stress that the details must be made known in advance.
• Simplicity is about how easy the tax system is to understand, which is not the same as knowing the exact amount and time.

4. Answer The correct option is D. Principle of certainty.

5. Exam tip Link each canon to a key word:

• Certainty → "Know the details" (amount, when, how)
• Convenience → "Comfortable" (time and method)
• Economy → "Cheap to collect"
• Equity → "Fair, ability to pay"

If the question says the taxpayer must know something, think certainty.