$($ Virgin Group case $)$ ?A fundamental question Virgin considers when starting a new venture is whether there is an opportunity for restructuring the market to their advantage. This represents an example of which of Porter's "essential tests"?

a $.$ ?The "attractiveness" test.

b $.$ ?The "cost $-$ of $-$ entry" test.

c $.$ ?The "better $-$ off" test.

d $.$ ?Value Chain Profitability test.

e $.$ ?None of the above.