Answer
(a) A basis for the row space is given by
$$S=\{(1,-3,2),(0,35,7)\}.$$
(b) The rank of the matrix is $2$.
Work Step by Step
Let $A$ be given by $$
A=
\left[\begin{array}{ccc}{2} & {-3} & {1} \\ {5} & {10} & {6} \\ {8} & {-7} & {5}\end{array}\right]
$$
The reduced form of $A$ is given by
$$\left[ \begin {array}{ccc} 1&-3&2\\ 0&{35}&7\\ 0&0&0\end {array} \right]
$$
(a) A basis for the row space is given by
$$S=\{(1,-3,2),(0,35,7)\}.$$
(b) The rank of the matrix is $2$.