Question: Isitshudeni esisekilasini elingenalutho siyamemeza, "Sawubona!" Yikuphi okukuchaza kangcono loko lesi sitshudeni esikuzwayo ngemva kokumemeza?
Options:
ukukhula komsindo
impinda (reflection) yomsindo
i-frequency yomsindo eyandisiwe 
i-refraction yomsindo
Answer: B