Explanation:

First statement is correct. Garbhagriha or Garbha gruha is the sanctum sanctorum, the innermost sanctum of a Hindu temple where resides the murti (idol or icon) of the primary deity of the temple.
Mandapa: It is the entrance to the temple. It may be a portico or colonnaded (series of columns placed at regular intervals) hall that incorporates space for a large number of worshippers. Dances and such other entertainments are practiced here. Some temples have multiple mandapas in different sizes named as Ardhamandapa, Mandapa, and Mahamandapa.

Second statement is correct. There are also many subsidiary shrines within temple complexes, more common in the South Indian temple.
A Hindu temple is a Panchayatana one when the main shrine is surrounded by four subsidiary shrines.
Third statement is correct i.e. the late Gupta period saw temples being constructed in the Panchayatana style.
Panchayatana is an architectural style where the main shrine is built on a rectangular plinth with four smaller subsidiary shrines at the four corners and making it a total of five shrines – i.e., Pancha.
Fourth statement is incorrect. In north Indian temples, we can see images such as Mithunas (erotic) and the river goddesses, Ganga and Yamuna guarding the temple. But in the Dravida style of temple architecture, instead of these sculptures, we can see the sculptures of fierce dvarapalas or door keepers guarding the temple.