Answer : B and C
Explanation :
firstly, we should know the definition of square matrix. It is a matrix in which number of rows is equal to number of columns
In case of A : it is given that several number of airlines and several number of columns
if we consider the case of more number of airlines say 5 and we have only 4 cities that these 5 airlines offer services to. Then it will not form a square matrix
NOTE: it would have formed the square matrix if there would have been equal number of airlines and cities.
In case of B: in this case we will have equal number of members in each team.
In case of C : in this case we are given with equal number of equations and unknowns
In case of D: in this case we have augmented matrix which is formed by appending the column of the matrices given so it can never form a square matrix.
