A:
Monetary policy is when the government utilizes Changing interest rates and exchange rates to influence aggregate demand.
B:
Monetary policy and Fiscal Policy both aims to influence Aggregate demand; They both do this is wildly different ways and to achieve different outcomes, Monetary policy influences AD via influencing the interest rate and engaging in open markets to purchase securities(influencing the money supply) while Fiscal policy utilizes the technique of taxing and spending to influence aggregate demand.
C:
An increase in money supply would be helpful for the trade union since with the increase in money supply the companies would place larger orders for raw materials which will boost output. The amount of payment made to members in wages and other forms of compensation is a trade union's main issue. But with the increase in money supply the Firm would have an increased ability to sustain the higher wage or other forms of compensation that the trade union would bargain for since they can argue that the increased money supply leads to inflation which the firms should compensate for by increasing the wage that the workers receive, the increased money supply could lead to an increased in the workers hired due to the increased economic activity, which would lead to a higher bargaining power due to the increased work force(and members in the trade union.)
D:
The increase in interest rate could have a multitude of effects on consumer expenditure, One effect is that it might reduce it. This reduction in consumer expenditure could be caused by the increase in interest rate due to the increase in the amount of people saving their disposable income since it'll be more attractive to them since they could earn a higher amount of passive income before, causing a decrease in consumer expenditure. Another reason is that the higher interest rate could cause a reduction in consumer expenditure is that loans would be higher which would discourage loans and discourage consumer consumption.
On the other hand, if the rate of increase is small, the impact on consumer expenditure could be very much limited, Consumers with stable incomes or low debt might not alter their spending habits or confidence. Households with very large amounts of saving could also benefit from high(er) interest income. For example, if someone have a large investment in bonds, they might spend more due to the increased interest income which will increase aggregate demand.