According to section 11.3, what are the strands of ELF approach? （ ）。
选项：

A:Students must know the linguistic features that may cause particular problems of mutual intelligibility.
B:The curriculum must focus on cultural differences and their implications for cross-cultural communication.
C:Students need to be taught the communicative strategies that aid successful cross-cultural communication.
D:The communicative strategies must be underpinned by the international community.