CDs are the least risky investment choice when compared to flipping, renting and bonds.

A certificate of deposit (CD) is a savings certificate with a fixed maturity date, specified fixed interest rate and can be issued in any denomination aside from minimum investment requirements. A CD restricts access to the funds until the maturity date of the investment. CDs are generally issued by commercial banks.

CDs are issued by the bank and are guaranteed by the government. So even if the bank goes bankrupt the investor's money is guaranteed to a certain extent.

Flipping and renting are subjected to market fluctuations while bonds are not insured.

Hierarchy is a system of ranking in which members of a particular society are ranked in an ascending order depending on various factors.

Hence, the term hierarchy refers to a power structure in which each member knows his or her own place.

RNA is not a lipid among the given options.

A lipid is a substance of biological origin that is soluble in nonpolar solvents. It comprises a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, and phospholipids.

Configuration management is not concerned with the choice of the hardware configuration for an application.

Configuration management is concerned with the development of procedures and standards for cost-effective managing and controlling charges in an evolving s/w system.

It includes

1)software versions maintenance

2)controlling changes in documentation

3)controlling changes to the source code

4) management activities

In a computer, memory is one part of Central processing unit i.e, CPU.

A karst topography is that which composes of limestone and its associated features and structures. Karst topography and caves develop in limestone rocks due to their solubility in dilute acidic groundwater. The solubility of limestone in water and weak acid solutions leads to karst landscapes.

Flowing rivers, can be found in areas away from karst topography.

There are lots of reasons behind the flood in any area but the main reason is a heavy downpour or rapid snowmelt can flood canyons with a mixture of soil, rock, and water is a major cause of floods.

When the spring times come, sometimes there's a lot of warmth that suddenly comes, especially nowadays when there are things such as global warming. So the snow melts and large amounts of water can flood the fields that are often found at the foot of a mountain or similar things.

But they may also be caused by deforestation, drainage channel modification from a landslide, earthquake or volcanic eruption. Examples include outburst floods and lahars.

We know that the time difference between India and USA is 9 hrs 30 min.

India is 9:30 hrs ahead of USA.

Time in India = 4:15 + 9:30 = 13:45 PM.

Required Time after 18 hrs = 13:45 + 18 hrs = 7:45 AM.

Hence it is 7:45 AM on the next morning.