When oil prices go up, we tend to see less investment by consumers in

When oil prices go up, the inverse effect can be seen on the demand as the consumers will do less investment in vehicles (less demand).  

Explanation:

Demand and Supply are two inseparable parts of the economy and these two aspects affects each other. Demand is what (quantity of goods and services) which the consumers was to but at a certain point of time and at the certain available price.

The supply and price has negative relationship. When the supply of goods and services increases in the market the price decreases. Supply depends on the price, when supply increases price decreases and vice a versa.

arresting and exicuting citizens

that would be the steamboat because none of the other things are forms of transportation