To calculate Ms. Tanaka's total earnings for selling 12 televisions, we will use the formula given:
\[ \text{Total Earnings} = 2500 + 100t \]
where \(t\) represents the number of televisions sold.
Substituting \(t = 12\):
\[ \text{Total Earnings} = 2500 + 100 \cdot 12 \]
Calculating \(100 \cdot 12\):
\[ 100 \cdot 12 = 1200 \]
Now, add that to the base salary:
\[ \text{Total Earnings} = 2500 + 1200 = 3700 \]
Therefore, Ms. Tanaka will earn $3,700 for selling 12 televisions this month.
The correct answer is $3,700.