The bright colours of ripe fruits is due to

The correct option is Chromoplasts.

Plastids are double-membrane-bound organelles found in the cells of plants and algae. They are classified into different types based on the pigments they contain and their primary functions:

1. Chromoplasts: These are plastids responsible for pigment synthesis and storage. They contain carotenoid pigments (like carotene and xanthophylls), which impart yellow, orange, and red colours to flowers, old leaves, and ripe fruits. The transition of green unripe fruit to bright-coloured ripe fruit occurs due to the transformation of chloroplasts into chromoplasts.
2. Chloroplasts: These plastids contain chlorophyll and carotenoid pigments, which are responsible for trapping light energy essential for photosynthesis. They give plants their green colour.
3. Leucoplasts: These are colourless plastids of varied shapes and sizes, which store nutrient reserves. Examples include amyloplasts (which store carbohydrates/starch), elaioplasts (which store oils and fats), and aleuroplasts (which store proteins).
4. Amyloplasts: A specific type of leucoplast, they are non-pigmented organelles responsible for the synthesis and storage of starch granules through the polymerization of glucose.

Therefore, the bright, vibrant colours of ripe fruits are specifically due to the presence of Chromoplasts.