The number of sign changes in the first column of the Routh's array denotes:

• A. the number of zeros of the system in Right half of s-plane
• B. the number of zeros of the system in left half of s-plane
• C. the number of open loop poles in Right half of s-plane
• D. the number of roots of characteristic equation in Right half of s-plane
• E. the number of roots of characteristic equation on the imaginary axis