下列离子方程式正确的是 [ ]

A．碳酸氢钠溶液与少量石灰水反应：HCO₃^－＋Ca²⁺＋OH^- ＝CaCO₃↓＋H₂O

B．氯化铵与氢氧化钠两种浓溶液混合加热：NH₄^＋＋OH^-H₂O＋NH₃↑

C．氢氧化镁与稀硫酸反应：H⁺ ＋OH^- ＝H₂O

D．单质铜与稀硝酸反应：Cu＋2H⁺ ＋2NO₃^－＝Cu²⁺ ＋2NO↑＋H₂O

Which of the following is least likely to be a requirement for a firm claiming compliance with Global Investment Performance Standards (GIPS)（）

A. List discontinued composites for at least five years.

B. Comply with all requirements and be aware of updates and guidance statements.

C. Provide a compliant presentation only to prospects who request one.