Choice Bhoice C is the correct answer.

1. Start with the equation: $\frac{x}{3} + 4 = 10$
2. Subtract 4 from both sides: $\frac{x}{3} = 10 - 4$
3. Simplify: $\frac{x}{3} = 6$
4. Multiply both sides by 3: $x = 6 \times 3$
5. Simplify: $x = 18$
6. Verify: $\frac{18}{3} + 4 = 6 + 4 = 10$ ✓

Choice Bhoice D is incorrect because this results from adding 4 to 10: $14$, then $14 \times 3 = 42$. Wrong inverse operation.

Choice Bhoice D is incorrect because this is the value of $\frac{x}{3}$. You must multiply by 3.

Choice Bhoice C is incorrect because this results from dividing 6 by 3: $2$. We need to multiply.