7. (a) Write a BNF (not EBNF) for the following type of arithmetic expressions. Arithmetic expressions only use + and - operators and variables A, B, C. The + operator has higher precedence than the - operator. (b) Write an EBNF (not BNF) for a list of statements. List has two or more statements. Each statement ends in a semicolon. Use to dennote a statement. Do not elaborate EBNF must be as compact as possible