meaning
I am from Korea however i am confused which one do i have to tick between the C and E.

A) White
B) Mixed
C) Asian or Asian British (Indian Pakistani Bangladeshi Any other Asian background)
D) Black or Black British
E) Chinese or Other Ethnic Group

and one more question,
What does it means : post applied for?

Question

meaning
I am from Korea however i am confused which one do i have to tick between the C and E.

A) White
B) Mixed
C) Asian or Asian British (Indian Pakistani Bangladeshi Any other Asian background)
D) Black or Black British
E) Chinese or Other Ethnic Group

and  one more question,
What does it means : post applied for?

Answer

You should tick box E.

In Britain, we generally use the term Asian for people from the Indian subcontinent (the nationalities shown). This category also covers the millions of British residents (mainly Muslims, Sikhs or Hindus) who have Indian, Pakistani and Bangladeshi heritage.

As a Korean visitor, you would not be included in this category.

Answer

'Post applied for' means: 'Job applied for'. A post is a job. If you are from Korea I would tick C but it is your choice - you can tick whichever one you identify as (feel closest to). Hope this helps. Will