Correct answer only !

looking at the above diagram at what point would the potential energy be the lowest?

This question is helping you find out whether you remember the formula for potential energy.  Do you

The formula is:  PE = (mass) (gravity) (height)

The mass isn't changing in this picture, and the gravity isn't changing either.  It's only the height that's changing.

Look at the formula and decide what height you need for the least potential energy.

Then look at the graph and decide where that height is.

the components of a vector are the parts of the vectors that are to each other.

b perpendicular