To acquire iron as a critical nutrient, pathogenic bacteria . invade cells in order to access iron within degradative lysozymes secrete lactoferritin that binds iron at very low concentrations degrade rust into a usable form of iron use adhesins to bind free iron within the host secrete proteases that degrade host factors such as hemin or hemoglobin in order to access the released iron.

The options include:

1. degrade rust into a usable form of iron

2. secrete proteases that degrade host factors such as hemin or hemoglobin in order to access the released iron

3.invade cells in order to access iron within degradative lysosomes

4.use adhesins to bind free iron within the host

5.secrete lactoferritin that binds iron at very low concentrations

The answer is

2. secrete proteases that degrade host factors such as hemin or hemoglobin in order to access the released iron.

Due to the abundance of the pathogenic bacteria in their host , they are able to secrete enzymes known as protease which acts on protein component of the blood called Hemoglobin. This subsequent enzymatic action results in the release of iron for their use.