7. Given the following grammar for an expression language E: S : expr '$' [] [1] [2] 2 expr . term '@' term ; term : factor '%' term | factor ; factor : '&' factor : DIGIT '('expr ')' [3] [4] [5] [6] [7] where $ stands for the EOF marker and the terminal DIGIT stands for a token representing the digits o ... 9. a. Can the operand of the unary suffix operator @ be another unary @-expression without needing the operand to be surrounded by parentheses? 2-points b. Can the operand of the unary prefix operator & be another unary &-expression without needing the operand to be surrounded by parentheses? 2-points c. What is the associativity of the binary % operator? 2-points