An indefinite article is used when we are talking generally about something whereas a definite article is used when we are talking about something specific.
The indefinite articles are 'a' and 'an'. An is used before a word starting with a vowel or vowel sound.
The first blank is followed by words which act as a reference to the person we are talking about, so it won't take any article. The second blank will take 'a' as 'a' is followed by a noun complement.
'What sort of person is he? He is such a nice fellow.'
The correct answer is option A)no article,a.