The Mass in the Figure Below Slides on a Frictionless

Multiple Choice

The mass in the figure below slides on a frictionless surface. When the mass is pulled out, spring 1 is stretched a distance x1 from its equilibrium position and spring 2 is stretched a distance x2. The spring constants are k1 and k2, respectively. The force pulling back on the mass is ​
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A) −k2x1.
B) −k2x2.
C) −(k1x1 + k2x2) .
D) .
E) .