When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as :

The correct answer is Metacentric.

Chromosomes are classified into four main categories based on the position of the centromere (the region where two sister chromatids are joined and spindle fibers attach during cell division):

1. Metacentric chromosome: The centromere is located exactly or nearly in the middle, dividing the chromosome into two equal or approximately equal arms (p-arm and q-arm). During cell division, a metacentric chromosome typically assumes a 'V' shape.
2. Sub-metacentric chromosome: The centromere is situated slightly away from the center, leading to one slightly shorter arm (p-arm) and one longer arm (q-arm). These appear 'L' shaped during cell division.
3. Acrocentric chromosome: The centromere is located close to one end, resulting in one extremely short arm and one very long arm.
4. Telocentric chromosome: The centromere is positioned at the very terminal end of the chromosome, meaning it has only one visible arm.

Since the question specifies that the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred to as metacentric.