The Three Point Charges +4

Multiple Choice

The three point charges +4.0 μC,-5.0 μC,and -9.0 μC are placed on the x-axis at the points x = 0 cm,x = 40 cm,and x = 120 cm,respectively.What is the x component of the net electrostatic force exerted on the -9.0 μC charge by the other two charges? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

A) -0.55 N
B) 0.55 N
C) 0.64 N
D) 0.41 N
E) -0.41 N