Two students synthesized aspirin (lit. m.p. = 135°C) and measured melting points of their samples: Student A recorded 131-135°C and Student B recorded 133-134°C. Which statement is correct about these samples? a) Sample A is more pure than sample B. b) Sample A is less pure than sample B. c) Both samples are equally pure. d) Purity cannot be determined using melting point.