The answer is (a): The electroscope will indicate charge, as seen in the photograph below and in an mpeg video by clicking your mouse on the photograph.
Even with the system charged, the electroscope remains uncharged when it is inside the charged surface, because any charge introduced to a closed system remains on the outside of the conductor. However, when the seives are separated the electroscope becomes part of the surface, charge flows onto it, and the indicator shows that charge.
