1. This question is about lexing and parsing. (a) This question is about ASTs (= abstract syntax trees). For each of the following statements, state whether they are true or false. Each correct answer gives 2 marks, each wrong answer gets -1 mark, omitted answers get O marks. Overall marks are capped from below to 0. [10 marks] i. The AST is constructed by the lexer. ii. The AST is constructed by the parser. iii. The purpose of constructing an AST is to make later compiler phases (e.g. type-checking and code-generation algorithms) simpler. iv. The purpose of constructing an AST is to allow the compiler to generate faster executable machine code. v. The AST data type is a list of tokens