The number of various educational programs is increasing, _______ important roles have been realized by more and more people.

A．whose

B．where

C．which

D．that

下列反应的热化学方程式为：（1）C(s)＋O₂(g)＝CO₂(g) ；ΔH ₁＝－393.5kJ/mol 

（2）CH₃COOH（l）＋2O₂（g）＝2CO₂(g)＋2H₂O(l) ；ΔH ₂＝－870.3kJ/mol

（3）H₂(g)＋O₂(g)＝H₂O(l) ；ΔH ₃＝－285.8kJ/mol 

则反应2C(s)＋2H₂(g)＋O₂(g)＝CH₃COOH(l) 的ΔH为（  ）

A．488.3 kJ/mol

B．－488.3 kJ/mol

C．－244.15 kJ/mol

D．244.15 kJ/mol