Compare the prices of the following cars: Car A = ₹15,30,000, Car B = ₹15,28,500, Car C = ₹21,09,000, Car D = ₹21,90,000. Determine which car is more expensive in each comparison.

We compare ₹15,30,000 and ₹15,28,500.
Since $15,30,000 > 15,28,500$,

$$\text{Car A} > \text{Car B}$$

We compare ₹15,28,500 and ₹21,09,000.
Since $15,28,500 < 21,09,000$,

$$\text{Car B} < \text{Car C}$$

We compare ₹21,90,000 and ₹21,09,000.
Since $21,90,000 > 21,09,000$,

$$\text{Car D} > \text{Car C}$$

We compare ₹15,28,500 and ₹21,90,000.
Since $15,28,500 < 21,90,000$,

$$\text{Car B} < \text{Car D}$$

Final answers:

a) $\boxed{\text{Car A} > \text{Car B}}$

b) $\boxed{\text{Car B} < \text{Car C}}$

c) $\boxed{\text{Car D} > \text{Car C}}$

d) $\boxed{\text{Car B} < \text{Car D}}$