Find the unit vector in the direction of $a⃗=6î+3ĵ$.

• A. $â=3\surd5ĵ$
• B. $â=\frac{2\surd5}{5}î-\frac{\surd5}{5}ĵ$
• C. $â=\frac{2\surd5}{5}î+\frac{\surd5}{5}ĵ$
• D. $â=\frac{2\surd5}{5}î+\frac{3\surd5}{5}ĵ$