Of the following molecules, the which has  permanent dipole moment is :

BF_3​

In BF3​, the dipole moments cancel each other. Hence it does not have a permanent dipole moment.

SF_4​

The hybridization of a SF₄​ molecule is sp³d, thus a seesaw structure (bent because of lp-lp repulsion) and thus having a net dipole moment.

SiF_4​

In SiF_4​ the dipole moments cancel each other. Hence it does not have a permanent dipole moment.

XeF₄​-has a planar structure, so it is non-polar

SF₄​ - has a permanent dipole.