The question is in Vietnamese and asks about the coordinates of the vector j in a 3D coordinate system $Oxyz$.

To solve this:

1. In a 3D Cartesian coordinate system, the standard basis vectors are defined as:

   • i = (1, 0, 0), which is aligned with the x-axis,
   • j = (0, 1, 0), which is aligned with the y-axis,
   • k = (0, 0, 1), which is aligned with the z-axis.

2. The question asks for the coordinates of the vector j. By definition, the vector j is (0, 1, 0), meaning it has no component in the x or z directions, but a component of 1 in the y direction.

3. Now, looking at the options:

   • A: (1, 1, 1)
   • B: (1, 0, 1)
   • C: (0, 1, 0) ← This is the correct answer.
   • D: (1, 1, 0)

Since j = (0, 1, 0), the correct choice is C.

Would you like more details, or do you have any questions about this explanation?

Here are 5 related questions:

1. What are the coordinates of the vector i in a 3D space?
2. How are the standard basis vectors used in vector operations like dot product and cross product?
3. What are the properties of vector k in the coordinate system?
4. How do you represent a vector as a linear combination of i, j, and k?
5. How can you determine the direction of a vector given its coordinates?

Tip: Always remember the standard basis vectors in 3D space: i = (1, 0, 0), j = (0, 1, 0), and k = (0, 0, 1).