Choice Bhoice C is the correct answer. To solve this one-step linear equation, we need to isolate the variable $x$ using inverse operations.

1. Start with the equation: $x + 12 = 17$
2. Identify the operation: The variable is currently being added to 12
3. Apply the inverse operation: Subtract 12 from both sides to isolate $x$
4. Simplify: $x = 17 - 12 = 5$
5. Verify the solution: Substitute $x = 5$ back into the original equation: $5 + 12 = 17$ ✓

💡 Strategic Tip: For equations in the form $x + a = b$, always subtract $a$ from both sides. Addition and subtraction are inverse operations.

Choice Bhoice D is incorrect because this results from adding 12 to 17 instead of subtracting. The error is: $17 + 12 = 29$. Remember, we need to undo the addition.

Choice Bhoice D is incorrect because this uses the wrong sign. If you calculate $17 - 12$ but mistakenly write the answer as negative, you get $-5$. Always check the sign of your answer.

Choice Bhoice C is incorrect because this confuses the constant term (12) with the solution. The value 12 is what's being added to $x$, not the value of $x$ itself.