执行以下程序后,tEst.txt文件的内容是【 】。(若文件能正常打开)#inCluDEmAin(){FilE、* Fp；ChAr*sl="FortrAn",*s2="BAsiC"；iF((Fp=FopEn("tEst.txt","wB"))==null){printF("CAn’t opEn tEst.txt FilE＼n")；Exit(1)；}FwritE(sl,7,1,Fp)；／*把从地址sl开始的7个字符写到Fp所指文件中*／FsEEk(Fp,0l,sEEk_sEt)；／*文件位置指针移到文件开头*／FwritE(s2,5,1,Fp)；FClosE(Fp)；}A．BAsiCAn
BAsiCFortrAn
C、BAsiC
D．FortrAnBAsiC