Which of the following statements is/are true?(i) An informal organisation exists within every formal organisation(ii) The objectives of the informal organisation may be at odds with those of the formal organisation(iii) A strong, close-knit informal organisation is desirable within the formal organisation
选项：

A:Statement (i) only;
B:Statements (i) and (iii) only ;
C:Statements (ii) and (iii) only;
D:Statement（i）and (ii) only