There are 13 chambers in heart of cockroach . these chambers are closed at an end and they pump the blood into anterior aorta bcoz of alary muscles contraction from where it goes to perineural sinus and then to perivisceral sinus and then through ostia it enters the heart again and the cycle continues.

The correct answer to the question is option 'C', which is 13 chambers.

The heart of a cockroach is a long, tubular structure that runs along the length of its body. It is located in the upper part of the abdomen, just below the dorsal surface. The cockroach heart is a simple tube-like structure, and it is divided into several chambers.

The heart of a cockroach consists of the following chambers:

1. Ostia: The ostia are openings in the heart that allow blood to enter. There are 13 pairs of ostia in the cockroach heart.

2. Anterior Chamber: The first chamber of the heart is called the anterior chamber. It receives blood from the ostia and pumps it forward.

3. Aortic Chambers: Following the anterior chamber, there are several aortic chambers in the cockroach heart. These chambers are responsible for pumping the blood forward through the aorta.

4. Posterior Chamber: The last chamber of the cockroach heart is called the posterior chamber. It receives blood from the aortic chambers and pumps it into the hemocoel, which is the body cavity of the cockroach.

So, the cockroach heart consists of 13 chambers in total. It receives blood through the ostia and pumps it forward through the aorta, ultimately supplying oxygen and nutrients to the different parts of the cockroach's body.

In conclusion, the correct answer to the question is option 'C', which is 13 chambers.