Correct option is (B) 7
Crystal structure is basically an array of crystal lattice and crystal lattice is an array of unit cell joins together in a particular order. Just like a cell is the building block of a human body in the same way the unit cell is the building block for crystal structure. If we study the properties of a unit cell then we get the property of the whole crystal lattice.
There are in total seven crystal systems corresponding to 14 Bravais lattices. The seven crystal systems are triclinic system, monoclinic system, orthorhombic system, trigonal system, hexagonal system, tetragonal system and cubic system.
There are basic parameters in a unit cell that are a, b and c that refer to the sides of the unit cell and alpha, beta and gamma as the angle made in between y z axis, z x axis and x y axis respectively in a unit cell. One or more than one parameter changes correspond to a change in the crystal system.
