in a certain region of space, the gravitational field is given by -k/r,where r=distance,k=const.if gravitational potential at r=r0 be v0,then what is the expression for the gravitational potential v? options 1)k log(r/ro) 2)k log(ro/r) 3)vo+k log(r/ro) 4)vo+k log(ro/r) plz help me out I will mark u as brainliest if u answer correct