Answer:
Option a
Step-by-step explanation:
The efficient-market theory relates to the financial economics concept which claims that asset values represent all the knowledge available. The direct inference is that it is difficult to reliably "outperform the market" on a threat-adjusted basis because stock rates will respond only to fresh knowledge.
Thus, she is building her portfolio by including an index fund, which are the funds that are managed by copying a particular index of some proclaimed funds such as S and P etc.