Answer:
Coccus.
Step-by-step explanation:
Bacteria mostly exists in varying forms and varying shapes.
On the background of shape they are classified as:
Cocci (coccus is singular) - spherical in shape...✔✔✔
Bacilli (bacillus is singular) - as the shape of a rod
Spirillum - the bacteria appears to be the twisted shaped type
Nucleoid - the bacteria have a nucleus like shape or irregularly shaped form.
If a bacteria is seen to occur in many varying shapes it is termed as pleomorphic.
The attached image gives clarity to the answer.