Which of the following elements is a metalloid?

Considering the atomic number and position in the periodic table,arrange the following elements in the increasing order of metallic character: $Si$,$Be$,$Mg$,$Na$,$P$.

Which of the following elements is considered as a metalloid?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R.$
Assertion $A :$ Metallic character decreases and non-metallic character increases on moving from left to right in a period.
Reason $R :$ It is due to increase in ionisation enthalpy and decrease in electron gain enthalpy,when one moves from left to right in a period.
In the light of the above statements,choose the most appropriate answer from the options given below :

Aluminium is diagonally related to (in periodic table)

Which one of the following combinations represents a metallic element?