For the word, a contextual sentence is given. Pick the word from the alternatives given, that is most inappropriate in the given context.
OBVIATE: The new mass transit system may obviate the need for the use of personal cares
Obviate means Remove a need or difficulty, avoid or prevent something undesirable. Forestall means, prevent or obstruct an anticipated event or action by taking advance action. Preclude means prevent from happening; make impossible. Option prevent is used negatively. But option Bolster means to support or strengthen is positive in meaning.
Therefore, Bolster is the correct answer.