a. we can see that it increases by 1 on each side, therefore figure 4 would be 5 horizontal squares and 5 vertical squares and figure 5 would be 6 horizontal squares and 6 vertical squares.
b. The pattern increases 1 horizontal square and one vertical square, which means that in total it grows 2 squares.
c. Figure 0 would be a single square since in figure 1 there are 3 squares, so if we follow the pattern, there will be only one square