<prompt> According to weins modification of the working length determination if bone resorption is there then:Reduce the length by 0.5mmReduce the length by 1mmReduce the length by 1.5mm.Reduce the length by 2mm.  <response>: Wein modification of working length determination by radiograph: 1. Reduce length by 1 mm if NO root bone resorption 2. Reduce length by 1.5 mm if bone resorption 3. Reduce length by 2 mm if both root and bone resorption 