Which of the following equations are correctly balanced?

$\bold{A.} \quad \phantom{X}^{q-1}${p-5}X \longrightarrow \phantom{X}^{q-5}{p-3}Y + \phantom{X}^{4}{2}He \\[1em] \bold{B.} \quad \phantom{X}^{q-4}{p-4}Z \longrightarrow \phantom{X}^{q-4}{p-5}X + \phantom{X}^{\phantom{1}0}{-1}e \\[1em] \bold{C.} \quad \phantom{X}^{q-1}{p-5}X \longrightarrow \phantom{X}^{q-5}{p-7}Y + \phantom{X}^{4}{2}He \\[1em] \bold{D.} \quad \phantom{X}^{q-4}{p-7}Z \longrightarrow \phantom{X}^{q-4}{p-5}X + \phantom{X}2^{\phantom{1}0}{-1}e \\[1em]

1. Only D
2. Only C
3. Both A & B
4. Both C & D

The below picture shows three cylinders filled with water to a different extent. The tuning forks L, M and N in vibration produce louder sound when held above the mouth of the cylinders. Which combination is correct for hearing a louder sound of the tuning fork?

1. L – R, M – Q, N – P
2. L – P, M – Q, N – R
3. L – R, M – P, N – Q
4. L – Q, M – R, N – P

The below diagram shows different copper conductors of diameters d and 2d and lengths, which are multiples of l. The increasing order of their resistances will be:

1. A < B < C < D
2. A < C < D < B
3. A < D < C < B
4. D < A < C < B

The diagram shows the magnificent dome at Gol Ghumbaz at Bijapur. A boy standing at A whispers, and it is clearly heard at B across the huge dome.

[Speed of sound is 330 ms^-1]

Assertion (A) : The distance travelled by sound waves (x+y) should be < 33 m.

Reason (R) : Sound reflected within 0.1 s is not heard by humans.

1. A and R are true, and R is the reason for A.
2. A and R are true, and R is not the reason for A.
3. A is true, but R is false.
4. A is false, but R is true.