2-quasirecognizability of the simple groups B_n(p) and C_n(p) by prime graph

Let G be a finite group and let GK(G) be the prime graph of G. We assume that n is anodd number. In this paper, we show that if GK(G)=GK(B_n(p)), where n geq 9 and p in{3,5,7}, then G has a unique nonabelian composition factor isomorphic to B_n(p) orC_n(p) . As consequences of our result, B_n(p) is quasirecognizable by its spectrumand also by a new proof, the validity of a conjecture of W. J. Shi for B_n(p)is obtained.