Use the contour diagram of $f$ in the figure below to decide if the specified directional derivatives below are positive, negative, or approximately zero.

(a) At point $(-2,2)$, in direction $\overrightarrow i$:   $f_{\overrightarrow u}\ $ is ? positive negative approximately zero

(b) At point $(0,-2)$, in direction $-\overrightarrow j$:   $f_{\overrightarrow u}\ $ is ? positive negative approximately zero

(c) At point $(-1,1)$, in direction $\overrightarrow i + \overrightarrow j$:   $f_{\overrightarrow u}\ $ is ? positive negative approximately zero

(d) At point $(-1,1)$, in direction $-\overrightarrow i + \overrightarrow j$:   $f_{\overrightarrow u}\ $ is ? positive negative approximately zero

(e) At point $(0,-2)$, in direction $\overrightarrow i + 2\overrightarrow j$:   $f_{\overrightarrow u}\ $ is ? positive negative approximately zero

(f) At point $(0,-2)$, in direction $-\overrightarrow i - 2\overrightarrow j$:   $f_{\overrightarrow u}\ $ is ? positive negative approximately zero