[DS10.C1.1.BT.a] Mệnh đề nào sau đây đúng?
A.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20205531505337129030/obj20205531505337129030587468_images/obj20205531505337129030587468_img1.png)
B.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20205531505337129030/obj20205531505337129030274400_images/obj20205531505337129030274400_img1.png)
C.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20205531505337129030/obj20205531505337129030559341_images/obj20205531505337129030559341_img1.png)
D.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20205531505337129030/obj20205531505337129030720242_images/obj20205531505337129030720242_img1.png)
Đáp án và lời giải
Đáp án:A
Lời giải:
Vì
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20205531505337129030/obj20205531505337129030394579_images/obj20205531505337129030394579_img1.png)