c
(c)
Pressure at the bottom of sea $=\rho_w g h=1000 \,kg / m ^3 \times 10 \,m / s ^2 \times 1400 \,m =14000000 \,N / m ^2$
Also we know
$\frac{\Delta v}{v}=-\frac{P}{B} \quad\left\{\frac{\Delta v}{v}=\frac{-2}{100}\right\}$
$\frac{-2}{100}=\frac{-14000000}{B}$
$B=7 \times 10^8 \,N / m ^2$