Teacher

For admission in NTT course, you need to have passed 10+2 from a recognised university.

To become a teacher, you have to pursue B.Ed course, because B.Ed makes you eligible for teaching job in whatever subject you want. If you have completed graduation degree in computer Science, then you are eligible for High School teacher exam but B.Ed degree is essential for government school jobs.

Hello Vinita,
It's nice to know that you are interested in doing PhD. Almost all universities conduct entrance exam to weed out no serious students. Once you clear this entrance test, you need to look out for a guide in your subject. After this, with advise of guide, select your research topic, register by paying fees and you are on your way.

You are eligible for PGDM General Management in XLRI. Your 5 years of experience as elementary school teacher will be counted as valid work experience.

Yes, you are eligible to become a professor. After qualifying, you can apply for posts of assistant professor in higher level educational institutions. If you qualifies JRF, then you are eligible to pursue research and apply for the post of JRF in higher level educational institutions. All the best.

Yes, B.Ed degree from any recognized and certified university is enough for applying for government teachers exams. All the best.

Since you have completed your MBA, and you want to go in teaching field, so you can go for:
NTT
PTT
BTC
D. El. Ed. B. El. Ed. B.Ed etc.