Step 1: Check Statement (A).
An ideal liquid is incompressible.
So, its volume does not change under pressure.
Hence, its bulk modulus is infinite.
Also, a liquid cannot sustain shear stress, so its shear modulus is zero.
Therefore, Statement (A) is true.
Step 2: Check Statement (B).
Bulk modulus is given by
\[
K=-\frac{P V}{\Delta V}
\]
So,
\[
\Delta V=-\frac{PV}{K}
\]
Given,
\[
P=7\times 10^6\,\text{Pa}
\]
\[
K=140\,\text{GPa}=140\times 10^9\,\text{Pa}
\]
Edge of cube:
\[
10\,\text{cm}=0.1\,\text{m}
\]
Volume:
\[
V=(0.1)^3=10^{-3}\,\text{m}^3
\]
Thus,
\[
\Delta V=-\frac{(7\times 10^6)(10^{-3})}{140\times 10^9}
\]
\[
\Delta V=-5\times 10^{-8}\,\text{m}^3
\]
This is not equal to
\[
-0.05\,\text{m}^3
\]
Therefore, Statement (B) is false.
Step 3: Check Statement (C).
When a spiral spring is stretched by attaching a weight, its length increases.
Increase in length corresponds to tensile strain.
Therefore, Statement (C) is true.
Step 4: Final conclusion.
Hence,
\[
\boxed{\text{A, C are true, B is false}}
\]