Comprehension \( \quad \) : A charged particle is suspended at the center of two thin concentric...

Comprehension \( \quad \) : A charged particle is suspended at the center of two thin concentric spherical charged shells, made of non conducting material. Figure A shows cross section of the arrangement. Figure B gives the net flux \( \phi \) through a Gaussian sphere centered on the particle, as a function of the radius \( r \) of the sphere.
Figure A
Figure B
What is the charge on shell \( A \) ?
(a) \( 5.31 \times 10^{-6} \mathrm{C} \)
(b) \( -5.31 \times 10^{-6} \mathrm{C} \)
(c) \( -3.54 \times 10^{-6} \mathrm{C} \)
(d) \( -1.77 \times 10^{-6} \mathrm{C} \)