Correct Answer - Option 3 : (1, 1, 1)

**CONCEPT**:

Perpendicular distance of a plane ax + by + cz + d = 0 from a point P (x_{1}, y_{1}, z_{1}) is given by: \(d = \left| {\frac{{a{x_1} + b{y_1} + c{z_1} + d}}{{\sqrt {{a^2} + {b^2} + {c^2}} }}} \right|\)

**CALCULATION**:

Let A(x, y, z) be the foot of the perpendicular drawn from the origin to the plane x + y + z = 3.

As we know that, the perpendicular distance of a plane ax + by + cz + d = 0 from a point P (x1, y1, z1) is given by: \(d = \left| {\frac{{a{x_1} + b{y_1} + c{z_1} + d}}{{\sqrt {{a^2} + {b^2} + {c^2}} }}} \right|\)

So, the distance between the origin and the plane x + y + z - 3 = 0 is given by: \(d = \left| {\frac{{0 + 0 + 0 - 3}}{{\sqrt {{1^2} + {1^2} + {1^2}} }}} \right| = \frac{3}{\sqrt 3} = \sqrt 3\)

So, this means that the length of the line joining the points origin and A is √3

As we can see that from the given options, if A = (1, 1, 1) then the distance between the points origin and A is √3

Hence, correct option is 3.