Explanation:

- We are given the speed of the stream as 2 km/h.

- Let the speed of the boat in still water be 'b' km/h.

- Upstream speed = b - 2 km/h and downstream speed = b + 2 km/h.

- Distance covered upstream in 4 hours: Distance = Speed × Time = 4(b - 2) km.

- Distance covered downstream in 3 hours: 3(b + 2) km.

- The downstream distance is 2 km less than the upstream distance:

$$3(b + 2) = 4(b - 2) - 2$$

- Solving the equation, we get:

$$3b + 6 = 4b - 8 - 2$$

$$3b + 6 = 4b - 10$$

$$4b - 3b = 16$$

$$b = 16$$

- Distance covered upstream: 4(b - 2) = 4(16 - 2) = 4 × 14 = 56 km.

- Therefore, the correct option is:

Option: 1, 56 km