Manhattan SC guide at page 76 (Ch-5) says that: "The pronoun that can be used to modify either people or thing". But the OG-11 at SC Q-130 says that: "The pronoun who, rather than that , should be used to refer to people".
The grammars I have read (e.g. Oxford's A Practical English Grammar) also say that that can be used for both people and things. Please clarify.
Nauman