What is the net investment coefficient?

a) Investment is an essential economic activity because it increases the amount of capital available for future production.
b) Net investment is equal to gross investment minus depreciation.
c) Gross investment includes all investment goods produced, while net investment adjusts for depreciation.
d) The net investment coefficient is used to estimate the formation of capital.
e) Only tangible capital is considered investment in economics.
f) Private investment is composed of gross fixed capital formation and inventory variation.