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We have the relation
$$\frac{{}{}^{\,n+2}C_6}{{}^{\,n-2}P_2}=11.$$
First we recall the standard formulas:
Combination formula $$\,{}^rC_k=\dfrac{r!}{k!(r-k)!}.$$
Permutation formula $$\,{}^rP_k=\dfrac{r!}{(r-k)!}.$$
Using these, we write the two terms appearing in the given ratio.
For the numerator
$$ {}{}^{\,n+2}C_6=\frac{(n+2)!}{6!\,(n+2-6)!} =\frac{(n+2)!}{6!\,(n-4)!}. $$
For the denominator
$$ {}^{\,n-2}P_2=\frac{(n-2)!}{(n-2-2)!} =\frac{(n-2)!}{(n-4)!}. $$
Hence the given ratio becomes
$$ \frac{{}{}^{\,n+2}C_6}{{}^{\,n-2}P_2} = \frac{\dfrac{(n+2)!}{6!(n-4)!}} {\dfrac{(n-2)!}{(n-4)!}} = \frac{(n+2)!}{6!(n-2)!}. $$
Now we simplify the factorial quotient:
$$ \frac{(n+2)!}{(n-2)!} = (n+2)(n+1)n(n-1), $$
because the factors from $$(n-2)!$$ downward cancel completely inside $$(n+2)!$$.
So the ratio equals
$$ \frac{(n+2)(n+1)n(n-1)}{6!} = \frac{(n+2)(n+1)n(n-1)}{720}. $$
The problem states that this ratio is $$11$$, therefore
$$ \frac{(n+2)(n+1)n(n-1)}{720}=11. $$
Multiplying both sides by $$720$$ gives
$$ (n+2)(n+1)n(n-1)=7920, $$
because $$11\times720=7920$$.
The left‐hand side is the product of four consecutive integers. We can try successive integral values for $$n$$ near the fourth root of $$7920$$.
Checking $$n=9$$:
$$ (9+2)(9+1)\cdot9\cdot(9-1)=11\cdot10\cdot9\cdot8 =110\cdot72=7920. $$
Thus $$n=9$$ satisfies the equation.
Now we see which of the given quadratic equations becomes true when $$n=9$$.
Option A: $$n^2+n-110=9^2+9-110=81+9-110=-20\neq0.$$
Option B: $$n^2+2n-80=81+18-80=19\neq0.$$
Option C: $$n^2+3n-108=81+27-108=0.$$
Option D: $$n^2+5n-84=81+45-84=42\neq0.$$
Only Option C is satisfied.
Hence, the correct answer is Option C.
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