To find out the total storage your mobile phone would have if you buy the additional bytes, you need to add the current storage to the additional storage.
Current storage:
\( 1.28 \times 10^{11} \) bytes
Additional storage:
\( 384,000,000,000 \) bytes = \( 3.84 \times 10^{11} \) bytes (to convert it to scientific notation)
Now, let's add the two amounts:
\[ 1.28 \times 10^{11} + 3.84 \times 10^{11} = (1.28 + 3.84) \times 10^{11} = 5.12 \times 10^{11} \]
Therefore, if you buy the additional bytes, your phone would have:
\[ 5.12 \times 10^{11} \text{ bytes} \]
So the correct answer is:
5.12 * 10 ^ 11