The correct option is B xy=c
x2−y2=cForming DE by eliminating arbitary constant2x−2ydydx=0dydx=xySo, DE for orthogonal trajectorydydx=−yxSeparating variables and integratingdyy+dxx=0lny + ln x= kln xy = kEquating arbitary constant k to ln cln xy= ln cxy=c.This is the required orthogonal trajectory.