•   The value of goods and services produced by the citizens of a nation irrespective of the geographical limits in a financial year is known as GNP.

•   Gross national product at factor cost (GNPFC) is the sum total of factor income earned by citizens of a country during an accounting year, including depreciation.

GNP AT FACTOR COST = GNP AT MARKET PRICE – NET INDIRECT COST (DEPRECIATION)

•   The standard of living is a term used to describe the level of income, necessities, luxury, and other goods and services that are generally readily available to a designated population.

•   It is basically a metric that evaluates the amount of material goods that are produced and sold within a specified geographic area – such as a community, province, state, or country.

•   GDP per capita only measures the income paid to those residing in the country's borders. GNP per capita can raise a country's standard of living. That's because many citizens live in other countries to get better jobs. They also remit part of their wages back to their families at home. Hence, option a is correct.

•   In addition to GDP or GDP per capita,or GNP  at Factor Cost the main factors that are usually used in any calculation of the standard of living are other readily quantifiable economic factors – such as average income, consumer spending, housing prices, the poverty rate in an area, available goods and services, the rate of inflation (Factor cost), and employment levels.

•   Other factors that may be included in examining the standard of living in an area are things such as access to medical care, educational opportunities, infrastructure, housing affordability, climate, crime rate, and the level of economic stability in the area.

•   The relative health of the population – frequently measured using the metric of life expectancy – is also a factor considered when evaluating the standard of living.

•   Net national product (NNP) refers to gross national product (GNP), i.e. the total market value of all final goods and services produced by the factors of production of a country or other polity during a given time period, minus depreciation.