The letter tiles given are H, O, N, E, S, T. There are no letter A tiles among them.
The probability of selecting letter A is calculated as follows:
\[ \text{Probability} = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]
In this case, the number of favorable outcomes (selecting A) is 0, and the total number of letter tiles is 6.
\[ \text{Probability of selecting A} = \frac{0}{6} = 0 \]
So the correct answer is 0.