Cross-resistance can be one way or two way, one-way resistance can be seen in:
Neomycin and streptomycin
Tetracycline and doxycycline
Sulphadiazine and sulphadoxine
None of the above
Organisms that develop resistance to an antimicrobial agent may also show resistance to other  chemically related AMAs. The cross-resistance among AMAs could either be one-way or two-way.  Cross-resistance among tetracyclines and sulphonamides is usually ‘two-way’.