Correct Answer :
A. break down
Education is central is highlighting the importance and role, electronic networks and software-driven technologies have. The sentence has a positive connotation.
Option (a) is correct, because break down refers to falling apart or collapsing, or failure to function and the barriers are physical or metaphorical walls which hinder free movement, hence, this is the appropriate word.
Option (b) is wrong, because break refers to destroying the integrity of or get ruined, but as we are talking about barrier, break down is more appropriate.
Option (c) is wrong, because crumble means break into pieces.
Option (d) is wrong, because dismantle can be considered synonymous with crumble.