Major railway junctions in Andhra Pradesh include:

Vijayawada
Secunderabad
Visakhapatnam
Both a and c

The correct answer is: Both a and c.

Vijayawada and Visakhapatnam are major railway junctions in Andhra Pradesh.

Vijayawada is a city in the Indian state of Andhra Pradesh. It is the headquarters of the Vijayawada district and the capital of Andhra Pradesh. The city is located on the banks of the Krishna River, about 250 kilometers (160 mi) north of Chennai. Vijayawada is a major railway junction and is well-connected to other parts of India. The city is also a major commercial and industrial center.

Visakhapatnam is a city in the Indian state of Andhra Pradesh. It is the headquarters of the Visakhapatnam district and the second largest city in Andhra Pradesh. The city is located on the Bay of Bengal, about 600 kilometers (370 mi) east of Chennai. Visakhapatnam is a major port city and is well-connected to other parts of India. The city is also a major industrial and commercial center.