(A) ** to add
(B) to remove
(C) to stop
(D) to improve
EXPLANATIONS BELOW
Concept note-1: -annex in American English to add to as a condition, consequence, etc. 3. to incorporate into a country, state, etc. the territory of (another country, state, etc.)
Concept note-2: -: to attach as an addition : append. : to add (a territory) to one’s own territory to form a larger country. the United States annexed Texas in 1845.
Concept note-3: -Note: ‘Conquer’ and ‘conquest also means the same as ‘annex. ‘ Both these terms define the forceful annex of a territory.