Answer:
Option D is correct.
Step-by-step explanation:
Total number of letters = c , o , u , n , t
We have to find: Numbers of ways in which two letters can be choose.
Combination is used to find numbers of ways.
[tex]^{n}\textrm{C}_{r}=\frac{n!}{r!\times(n-r)!}[/tex]
Number of ways = [tex]^{5}\textrm{C}_{2}=\frac{5!}{2!\times(5-2)!}[/tex]
[tex]=\frac{5!}{2!\times3!}=\frac{5\times4}{2}=5\times2=10[/tex]
Therefore, Option D is correct.
