Question

which of the following is not a adverb. 1.loudly 2.quickly 3.friendly 4.softly

Answer 1

friendly is not an adverb
because
it is a quality
all the other words tell how a work is done

Answer 2

3. friendly.
Because:
'Loudly' can describe the verb 'speak'
'quickly' can describe the verb ' run'
'softly' can also describe the verb 'speak'
but friendly cannot describe any verb. It describes a noun, i.e., person. Like ' a friendly person'.