Match the LIST-I with LIST-II

The matching of reactions with their corresponding products is as follows:
A. Swarts reaction:
Produces Ethyl fluoride (IV) through the reaction:
R-Cl/Br + Metal fluoride → R-F
B. Sandmeyer's reaction:
Produces Cyanobenzene (III) through the reaction:
Ar-N2+Cl- + CuCN → Ar-CN
C. Wurtz-Fittig reaction:
Produces Ethyl benzene (I) through the reaction:
Ar-X + R-X + 2Na → Ar-R + 2NaX
D. Finkelstein reaction:
Produces Ethyl iodide (II) through the reaction:
R-Cl/Br + NaI → R-I + NaCl/NaBr
The correct matches are:
A-IV, B-III, C-I, D-II
If
$ 2^m 3^n 5^k, \text{ where } m, n, k \in \mathbb{N}, \text{ then } m + n + k \text{ is equal to:} $
A small point of mass \(m\) is placed at a distance \(2R\) from the center \(O\) of a big uniform solid sphere of mass \(M\) and radius \(R\). The gravitational force on \(m\) due to \(M\) is \(F_1\). A spherical part of radius \(R/3\) is removed from the big sphere as shown in the figure, and the gravitational force on \(m\) due to the remaining part of \(M\) is found to be \(F_2\). The value of the ratio \( F_1 : F_2 \) is: 
A uniform circular disc of radius \( R \) and mass \( M \) is rotating about an axis perpendicular to its plane and passing through its center. A small circular part of radius \( R/2 \) is removed from the original disc as shown in the figure. Find the moment of inertia of the remaining part of the original disc about the axis as given above.