Two very long line charges of uniform charge density \[+\lambda \]and \[-\lambda \]are placed along same line with the separation between the nearest ends being 2a, as shown in figure. The electric field intensity at point O is

• A. \[\frac{\lambda }{2\pi {{\varepsilon }_{0}}a}\]
• B. 0
• C. \[\frac{\lambda }{\pi {{\varepsilon }_{0}}a}\]
• D. \[\frac{\lambda }{4\pi {{\varepsilon }_{0}}a}\]