Nitrogen in the plant cell culture media is provided by either ammonia or nitrate salt. In the media

• A. utilization of ammonium cause culture pH to drop while utilization of nitrate cause culture pH to rise
• B. utilization of nitrate cause culture pH to drop while utilization of ammonium cause culture pH to rise
• C. utilization of both ammonium and nitrate result in rise in pH
• D. utilization of both ammonium and nitrate result in drop in pH