Select the most appropriate option to fill in the blank.

Highways are a catalyst for economic growth but private ______ in this sector has been termed 'tardy' as investors do not appear to be interested in putting their money in long-term projects.

investment

The most appropriate option to fill in the blank is:

☀ investment

Explanation for all options:

1. Contract: This term refers to a legally binding agreement between two or more parties. While contracts may be involved in infrastructure projects, the sentence is focused on private participation through financial contributions, making "contract" less fitting.

2. Transaction: This term refers to an exchange or interaction between parties involving the transfer of something of value. In the context, "transaction" doesn't convey the idea of long-term financial commitment that's being discussed.

3. Investment: This is the correct word. "Investment" refers to the act of putting money into something with the expectation of a return or profit. The sentence is discussing how private investment in the highways sector has been termed 'tardy,' indicating a lack of interest from investors.

4. Operation: This term refers to the functioning or management of a system, organization, or facility. It doesn't convey the financial aspect of putting money into a sector for growth.