A magnetic field existing in a region is given by $\mathrm{B}^{-}=\mathrm{B}_{0}[1+(\mathrm{x} / \ell)] \mathrm{k} \wedge . \mathrm{A}$ square loop of side $\ell$ and carrying
current I is placed with edges (sides) parallel to $\mathrm{X}-\mathrm{Y}$ axis. The magnitude of the net magnetic force experienced by the Loop is
(a) $2 \mathrm{~B}_{0} \overline{\mathrm{I} \ell}$
(b) $(1 / 2) B_{0} I \ell$
(c) $\mathrm{B}_{\circ} \mathrm{I} \ell$
(d) BI\ell