[tex] a_{n} = +(n-1)d [/tex]
We are given the first term and the common difference.
So,
[tex]a_{1}=-10 \\ \\ d=5[/tex]
Using these values in the given equation, we get:
[tex] a_{n} =-10+(n-1)*5 \\ \\
a_{n} = -10 + 5n - 5 \\ \\
a_{n} = 5n -15[/tex]
So, option C gives the correct answer.