You are provided with a sentence with one word missing,

Solution

'Intimidate' means to compel someone to do something one wants and 'prompt' means to cause someone to take a course of action; both fit into the context here. 'Dissuade' means to discourage, which does not fit into the context here, as the sentence tells us that the customer actually makes the purchase, instead of refraining from it. 'Inculcate' means to instill an idea by persistent instruction but it needs to be followed by either upon or in, so it won't fit into the sentence grammatically. Hence option a is the correct choice.