Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear?

Question

( A ) $CH_2 = CH – CH_2 – C ≡ CH $
( B ) $CH_3 – C ≡ C – CH_3$
( C ) $ CH_3 – CH = CH – CH_3 $
( D ) $ CH_3 – CH_2 – CH_2 – CH_3 $