To find the probability of selecting the letter A from the given letter tiles, we first need to determine how many tiles are in the box and how many of them are A.
The tiles provided are H, O, N, E, S, T. There is no letter A among these tiles, meaning there are 0 occurrences of the letter A.
The total number of tiles is 6 (H, O, N, E, S, T). The probability of selecting a letter A is given by the formula:
\[ \text{Probability} = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{0}{6} = 0 \]
Thus, the correct answer is:
0