Concept:
Since the hanging mass is larger, the \(4\,\text{kg}\) block moves downward and the \(3\,\text{kg}\) block moves upward along the incline.
Friction opposes the motion of the \(3\,\text{kg}\) block.
Step 1: Calculate the component of weight along the incline.
For the \(3\,\text{kg}\) block,
\[
W_{\parallel}
=
mg\sin37^\circ
=
3\times10\times0.6
=
18\,\text{N}.
\]
Step 2: Calculate the frictional force.
Normal reaction,
\[
N
=
mg\cos37^\circ
=
3\times10\times0.8
=
24\,\text{N}.
\]
Hence,
\[
f
=
\mu N
=
0.25\times24
=
6\,\text{N}.
\]
Step 3: Find the net driving force.
Weight of the hanging block,
\[
W=4g=40\,\text{N}.
\]
Opposing forces on the inclined block,
\[
18+6=24\,\text{N}.
\]
Therefore,
\[
F_{\text{net}}
=
40-24
=
16\,\text{N}.
\]
Step 4: Calculate the acceleration.
Total mass of the system,
\[
M
=
3+4
=
7\,\text{kg}.
\]
Hence,
\[
a
=
\frac{F_{\text{net}}}{M}
=
\frac{16}{7}
=
2.286\,\text{m s}^{-2}.
\]
\[
a
\approx
2.28\,\text{m s}^{-2}.
\]
Final Answer:
\[
\boxed{a=2.28\,\text{m s}^{-2}}
\]
\[
\boxed{\text{Answer = (A)}}
\]