Correct Answer - Option 4 : L = 2B + t

**Explanation:**

Brick length (L), width (B), and thickness of mortar (t) in the brick masonry are related to each by the relation:

L = 2B + t

Here mathematically,

Length of brick = 19 cm

Width of brick = 9 cm

Thickness of mortar = 1 to 1.2 cm

Modular Bricks:

Standard size of brick = 19 cm × 9 cm × 9 cm

Nominal size of a brick with mortar = 20 cm × 10 cm × 10 cm

Non Modular Bricks:

Conventional size of brick = 22.4 cm × 11.4 cm × 7.6 cm