The answer is (c.) They take the form of sporangia.
The Oomycota or Oomycetes is also known as water molds. In 1840, this type of genus ravaged some parts of Europe especially in Ireland. It is called the Irish Potato Famine. They are rarely to have septa or hyphae but if they do they appear at the bases of sporangia. They only appear on sporangia not takes its form.