Create a 2x2 cell array A with the following elements: 4x4 identity matrix; the string 'London is the largest city in world', the complex number (3+i*10); the array of N=20 numbers (of type single) representing the geometric progression with the base 5 and the common ratio 1/2. Replace the element 'London is the largest city in world' with 'London is a nice town'. Plot the created cell.