A. 190
B. 170
C. 230
D. 395
🧠 Explanation (Math):
Given: Choose 2 students from 20
Step 1: Use combinations $^{20}C_2=frac{20cdot19}{2}=190$.
Final Answer: 190A. 190
B. 170
C. 230
D. 395
Given: Choose 2 students from 20
Step 1: Use combinations $^{20}C_2=frac{20cdot19}{2}=190$.
Final Answer: 190