The number of words which can be formed out of the letters `a`, `b`, `c`, `d`, `e` `f` taken 3 together, each word containing one vowel at least is

Explanation

In the given letters, there are `2` vowels.

We have to form words using at least one vowel.

So, we can use either `1` or `2` vowel and remaining letters can be `4` consonants.

`:.` Required number of words ` = C(2,1)*C(4,2)+
C(2,2)*C(4,1)`

`= 2**(4**3)/(2**1)+1**(4) = 12+4 = 16`

So, correct answer is option `D`.