Which of these equations is correct? sqrt(16)+sqrt(9)=sqrt(16+9) sqrt(16)+sqrt(12)=sqrt(16+12) Neither is incorrect. b. Both are incorrect.

$\sqrt{16} + \sqrt{3} = \sqrt{16+3}$.
Calculate the left side (LS):

$$\sqrt{16} + \sqrt{3} = 4 + \sqrt{3}$$

Calculate the right side (RS):

$$\sqrt{16+3} = \sqrt{19}$$

Since $4 + \sqrt{3} \neq \sqrt{19}$, the first equation is incorrect.

$\sqrt{6} + \sqrt{12} = \sqrt{6+12}$.
Calculate the left side (LS):

$$\sqrt{6} + \sqrt{12} = \sqrt{6} + \sqrt{4 \times 3} = \sqrt{6} + 2\sqrt{3}$$

Calculate the right side (RS):

$$\sqrt{6+12} = \sqrt{18} = \sqrt{9 \times 2} = 3\sqrt{2}$$

Since $\sqrt{6} + 2\sqrt{3} \neq 3\sqrt{2}$, the second equation is incorrect.

Both equations are incorrect.

The final answer is $\text{d. Both are incorrect.}$.