एक हेक्सागोनल क्लोज-पैक्ड (HCP) संरचना की यूनिट सेल में लैटिस बिंदुओं (या परमाणुओं) की प्रभावी संख्या कितनी होती है?

The total effective number of atoms present in a Face-Centred Cubic (FCC) unit cell is:

The crystal structure of austenite is:

Which of the following options represents the correct sequence of crystal structures in decreasing order of their percentage of voids? (where SCC = Simple Cubic Cell, FCC = Face Centered Cubic, BCC = Body Centered Cubic)