Answer:
(a) Option (c) is correct.
(b) Option (b) is correct.
Step-by-step explanation:
(a) If there is an unexpected decrease in the oil prices (Positive supply shock) then as a result this will reduce the cost of production of the firms and hence, there is an increase in the supply of the goods. This will shift the aggregate supply curve rightwards.
(b) If all the producers are required to contribute more towards the heath insurance coverage (negative supply shock) then as a result this will increase the cost of production of the producers. So, this will lead to decrease the supply of the goods and also, shift the supply curve leftwards.