💡 Detailed Explanation
The correct choice is 'つもり' (intention / plan). The grammar pattern '[Verb Dictionary Form] + つもりだ' expresses the speaker's active intention or plan to do something. Sentence translation: 'I intend/plan to attend a cooking class starting next month.' 'こと' (matter) and 'よう' (looks like) do not express active personal intention directly. 'はず' expresses a logical expectation.