The bacteria culture doubles every hour. Starting with 100 bacteria, we can calculate the number of bacteria after \( n \) hours using the formula:
\[ \text{Number of bacteria} = \text{Initial amount} \times 2^n \]
Here, the initial amount is 100, and \( n \) is the number of hours (in this case, 12).
So we compute:
\[ \text{Number of bacteria after 12 hours} = 100 \times 2^{12} \]
Now, calculate \( 2^{12} \):
\[ 2^{12} = 4096 \]
Then we can find the total number of bacteria:
\[ 100 \times 4096 = 409600 \]
Thus, after 12 hours, the number of bacteria will be 409,600.
So the answer is 3) 409,600.