The__phase in the business cycle is a period when the level of business activity rises and gdp grows. (a) expansion (b) peak(c)contraction (d) trough

I would say expansion, because contraction and trough are bad for business. Peak is when everything is at its max point, not done growing or expanding.

I hope this helps :)

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b