Which of the following option is true?
(A) 25 straight lines can be formed by 8 points out of which 3 are collinear.
(B) 56 triangles can be formed by 8 points out of which 3 are collinear.
(C) 216 rectangles can be formed from a 3 x 8 grid.
(D) Both B and C are true.


Answer: (D)

Explanation: Straight lines can be formed by 8 points out of which 3 are collinear = ⁸C₂ – ³C₂ + 1 = 26
Triangles can be formed by 8 points out of which 3 are collinear = ⁸C₃ – ³C₃ = 56
Number of rectangle formed from a mxn grid = ^{m + 1}C₂ * ^{n + 1}C₂ = ⁴C₂ x ⁹C₂ = 216
So, option (D) is correct.

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