Q.3 solve this

Q.3 Let ​$\overrightarrow{\mathbf{a}}\mathbf{,}\overrightarrow{\mathbf{b}}\mathbf{,}\overrightarrow{\mathbf{c}}$  be three unit vectors such that $3\overrightarrow{\mathbf{a}}+4\overrightarrow{\mathbf{b}}+5\overrightarrow{\mathbf{c}}$ ​= 0. Then which of the following statements is true ? ​
(a) $\overrightarrow{\mathbf{a}}$ is parallel to $\overrightarrow{\mathbf{b}}$ 
(b) ​$\overrightarrow{\mathbf{a}}$ is perpendicular to $\overrightarrow{\mathbf{b}}$ 
(c) $\overrightarrow{\mathbf{a}}$ is neither parallel nor perpendicular to $\overrightarrow{\mathbf{b}}$ 
(d) none of the above