In the following question sentence given with blanks to be filled in with an appropriate word (S). Four alternatives are suggested for each question. Choose the correct alternative out of the four.Q. There are, as yet, no vegetation types or ecosystems whose study has been perfected to the extent that they no longer-------------------- ecologists.

In the following question sentence given with blanks to be filled in w

1.	In the following question sentence given with blanks to be filled in with an appropriate word (S). Four alternatives are suggested for each question. Choose the correct alternative out of the four.Q. There are, as yet, no vegetation types or ecosystems whose study has been perfected to the extent that they no longer-------------------- ecologists.
A.	Hinder
B.	Interest
C.	require
D.	challenge
Answer» E.