先阅读下列材料，然后解答问题：
材料1　从3张不同的卡片中选取2张排成一列，有6种不同的排法，抽象成数学问题就是从3个不同元素中选取2个元素的排列，排列数记为A₃²＝3×2＝6.
一般地，从n个不同元素中选取m个元素的排列数记作A_n^m，
A_n^m＝n(n－1)(n－2)…(n－m＋1)(m≤n)．
例：从5个不同元素中选3个元素排成一列的排列数为：A₅³＝5×4×3＝60.
材料2　从3张不同的卡片中选取2张，有3种不同的选法，抽象成数学问题就是从3个元素中选取2个元素的组合，组合数记为C₃²＝$\frac{3\times 2}{2\times 1}$＝3.
一般地，从n个不同元素中选取m个元素的组合数记作C_n^m，
C_n^m＝ $\frac{n\left(n-1\right)\cdots n-m+1}{m\left(m-1\right)\cdots 2\times 1}$(m≤n)．
例：从6个不同元素中选3个元素的组合数为：
C₆³＝$\frac{6\times 5\times 4}{3\times 2\times 1}$＝20.
问：(1)从7个人中选取4人排成一排，有多少种不同的排法？
(2)从某个学习小组8人中选取3人参加活动，有多少种不同的选法？

判断下列说法，正确的是（   ）

阅读下列短文, 从每题所给的四个选项（A、B、C和D）中选出最佳选项。

    With over 300 years of history, Harvard University, US, welcomed its first-ever Chinese commencement(毕业典礼) speaker. On May 26, He Jiang, a 2016 PhD（博士学位）graduate, gave a speech that stood for the graduate students at commencement. It's one of the highest honors for a Harvard graduate.

    In his speech, he told a story about his childhood. He grew up in a poor village in Hunan. Once a spider bit him on the hand, and his mother had to set his hand on fire to cure him. There were no doctors in the village, and this was the only cure a rural woman knew.

    When he got older, he couldn't help but think about why there wasn't a better cure at that time. And he thought out the answer ---- the unequal distribution of knowledge in the world.

     “Even today we haven't been very successful in bringing knowledge to where it's needed most,” said He. “Even basic life-saving knowledge we can get easily in the modern world is often unavailable in poor areas.” According to the China Children and Teenagers Foundation, there are still around 3 million children in China lacking education, and most of them live in rural areas.

     “One of the biggest problems for rural students is that they lack chances as well as motivation(积极性). It disturbs me that many people in rural areas think studying is useless.” Said He.

    But He Jiang knows how education can change people's lives. “I just hope my experience can give those rural students a bit of encouragement and hope,” said He.