Question

which observations can confirm that an object is a quasar? select all that apply. measured redshift is extremely large for a bright starlike source regular pulses of radio waves high variability in the objects luminosity radio jet associated with an optical source evidence of a rapidly expanding shell of material

Explanation:

Quasars are extremely distant and luminous objects. A large redshift for a bright starlike source indicates it is far - away and is a characteristic of quasars. High variability in luminosity is also typical as they are powered by accretion onto supermassive black holes. A radio jet associated with an optical source is another feature. Regular pulses of radio waves are more characteristic of pulsars, and evidence of a rapidly expanding shell of material is not a defining feature of quasars.

Answer:

measured redshift is extremely large for a bright starlike source
high variability in the object's luminosity
radio jet associated with an optical source