Given the following grammar:

::= +

| -

| *

| ( )

| a | b | c

Either draw the parse tree for the following strings, or indicate that the string is not in the language described by the grammar. MAKE SURE YOUR TREES ARE CLEAR/LEGIBLE TO READ, regardless if you draw by hand or do digitally.

a. (a + b) * (a c)

b. a c ( -b ) + a

c. ( b + (a) c )