Considerthe following equations:
1. $$A_1V_1 = A_2V_2$$
2. $$\frac{\partial u}{\partial x} + \frac{\partial v}{\partial y} = 0$$
3. $$\int_{s} pv.dA + \frac{\partial}{\partial t} \int_{v} pdV = 0$$
4. $$\frac{1}{r} \frac{\partial}{\partial r}(rv_r) + \frac{\partial}{\partial z}(v_s) = 0$$

A

Only 1

B

1 and 2

C

2 and 3

D

3 and 4