If they ask this question during your interview, your interviewer likely wants to see if you have a timeline. They are also curious about where they fall on your job wishlist. Job hunting is a numbers game. They don't expect you to put all your eggs in one basket, but they also don't want to hire someone who is just looking for any job. They want to know that you ideally want to work for them, and they want to know why. Honesty is always the best policy with this question, and it always puts a little fire under a hiring manager if they're aware that you're actively looking for a new position. Feel free to talk with the interviewer about your search so far and don't hesitate to let them know that a role with McKesson is at the top of your wishlist.

Keep an organized folder with every customized resume and cover letter you've submitted to each position you are interviewing for. The interviewer will have something similar for all the applicants they are interviewing. Have tabs separating your notes for each interview with a breakdown of the pro and cons of each employer. Detail, for your eyes only, what each of them offers you and what you offer them. Having this with you will present you as an organized professional taking all your prospects seriously. This will help market you as a viable candidate.