In the sample space \( S = {a, b, c, d, e, f} \), we first identify the consonants and vowels. The vowels in this set are \( a \) and \( e \). The consonants are \( b, c, d, \) and \( f \).
Counting the consonants, we have:
- Consonants: \( b, c, d, f \) (4 consonants)
- Vowels: \( a, e \) (2 vowels)
The total number of outcomes in the sample space is 6 (since there are 6 letters in total).
The probability of picking a consonant is calculated as follows:
\[ \text{Probability of consonant} = \frac{\text{Number of consonants}}{\text{Total number of outcomes}} = \frac{4}{6} \]
This fraction simplifies to:
\[ \frac{4}{6} = \frac{2}{3} \]
Thus, the probability of picking a consonant is \( \frac{2}{3} \).
The correct response is: \[ \frac{2}{3} \]