What should I select for the 'trip required' category when applying for a Guardian visa (non-immigrant O) for my child in Thailand?

Re. Guardian visa.

Does anyone know what we should select for the “trip required” category when applying online from the UK for a guardian visa (“non-immigrant O”) for a parent.

We’ve applied for the Ed visa for the child, but now trying to apply for the Guardian visa for her father. The drop-down menu only seem to include “study in primary education” (I.e. the student), and not the guardian. The only other ‘Non immigrant O’ visa option seems to be for those visiting family in Thailand, eg wife/husband or child.

Any ideas? Thanks — with Thomas Whitworth