6. Choose two different prime numbers between 4 and 18, then subtract their sum from their product, the resulting number can be ( ).
(A) 21
(B) 60
(C) 119
(D) 231
6.C.

Let the two chosen prime numbers be $x$ and $y$, and the resulting number be $T$, then
$$
T=xy-(x+y). 
$$
Thus,
$$
T+1=xy-x-y+1=(x-1)(y-1).
$$

Since $x$ and $y$ are both primes greater than 4, $x$ and $y$ are both odd, and $(x-1)$ and $(y-1)$ are both even. Therefore, $4 \mid (T+1)$.
However, $4 \times 22, 4 \nmid 61, 4 \mid 120, 4 \mid 232$, and
$$
T+1=232=2 \times 116=4 \times 58
$$

does not meet the requirements. Therefore,
$$
T+1=120=(11-1) \times (13-1), T=119.
$$