Two lines are said to be perpendicular to each other when they meet at ____angle.

• A. \[\text{180 }\!\!{}^\circ\!\!\text{ }\]      
• B. \[\text{90 }\!\!{}^\circ\!\!\text{ }\]  
• C. \[\text{60 }\!\!{}^\circ\!\!\text{ }\]                                  
• D. \[\text{360 }\!\!{}^\circ\!\!\text{ }\]