$\overrightarrow{A B}$ and $\overrightarrow{E F}$ are said to be skew lines because they neither intersect nor are parallel. How many planes are determined by
a) parallel lines $A B$ and $D C ?$
b) intersecting lines $A B$ and $B C ?$
c) skew lines $A B$ and $E F ?$
d) lines $A B, B C,$ and $D C ?$
e) points $A, B,$ and $F ?$
f) points $A, C,$ and $H ?$
g) points $A, C, F,$ and $H ?$
CAN'T COPY THE FIGURE