You are a technical support engineer for an IEEE $802\mathrm{.}11$ wireless network in a small office complex. You are called in to check with a user who has been complaining that the wireless network is running slowly. As you change the orientation of the user's notebook computer, you notice the signal strength varies. Change in which of the following results in this variation in signal strength $?$ AElevation B Azimuth CPolarity D Output power