Which of the following compounds will be suitable for Kjeldah1’s method for nitrogen estimation?

Which of the following compounds will be suitable for Kjeldahl's method for nitrogen estimation? (a) (b) (c) (d)

Which of the following compounds will be suitable for Kjedahl's method of nitrogen estimation-

In Kjeldahl's method, nitrogen is estimated as

In which of the following compounds Kjeldahl method is not applicable for estimation of ntirogen ?