A new relationship and a new marriage are different steps.
Divorced people may live with new partners. Two women may live together and may also marry if the legal requirements are met. A family with a single father is likewise not a prohibited way of life.
The fourth answer adds something different: the man would be in two legal marriages simultaneously. Section 1306 of the Civil Code prevents a new marriage while an existing one continues. This rule applies regardless of the sex of the people involved.

The other three answers
The other three living arrangements do not constitute marriage prohibitions.
A man and woman are divorced and live with new partners.
Living with new partners after divorce is permitted. The former marriage does not impose a lifelong ban on new relationships.
Two women live together.
Two women may live together. Marriage is also open to two people of the same sex, subject to the general requirements.
A single father lives with his two children.
A father may raise his children as a single parent. A family does not have to contain two cohabiting parents to be legally permitted.
The question does not settle complex foreign-law cases.
The learning point concerns the prohibition on entering another marriage under German law. Whether a family situation formed abroad has particular legal effects in Germany can raise separate questions that the short exam answer does not fully resolve.
Moving out, an argument or a new relationship does not itself end an existing marriage. Divorce depends on a final court decision. After a marriage ends, a later marriage may be possible if the other requirements are met.
Section 1306 · Existing marriage · Civil Code ↗Sharing a home is not the same as being married to several people simultaneously.
In this question, examine legal status rather than personal ideas about what a family should look like.
Three words for this question
- die Lebensformway of living
- The way people organise their personal daily lives and relationships.
- gleichzeitigsimultaneously
- At the same time, rather than one after another.
- rechtskräftigfinal and binding
- A court decision no longer open to ordinary appeal.
