A quadrilateral whose all opposite sides are parallel is called: (This question has multiple correct options)
A. a rhombus
B. a kite
C. a trapezium
D. a parallelogram

Hint: Here, in the given question, it is asked to specify the name (out of the given options) of the quadrilateral whose all sides are parallel. In order to get the answer to this question, we must know about the quadrilaterals and their special properties. Here, we will check the given options one-by-one and match the property given in the question and we will get our desired answer by moving forward this way.

Complete step-by-step answer:
‘Quadrilateral’ word is made up of two words, ‘quad’ which means ‘four’ and the word ‘lateral’ which means ‘side’. Therefore, a quadrilateral is a polygon having four sides.
Let us check all the options to find the quadrilateral which has all the opposite sides parallel.
For option (A), a rhombus
A rhombus is a quadrilateral having all the sides equal, and two pairs of parallel sides. It means rhombus has all the opposite sides parallel.
Therefore, option (A) is correct.
For option (B), a kite
A kite is a quadrilateral whose two pairs of sides are of equal length that are adjacent to each other. But opposite sides need not be parallel in kites.
Therefore, option (B) is incorrect.
For option (C), a trapezium
A trapezium is a quadrilateral whose exactly one pair of sides are parallel and others are not parallel.
All opposite sides are not parallel in trapezium.
Therefore, option (C) is incorrect.
For option (D), a parallelogram
Parallelogram is a quadrilateral having two pairs of opposite sides parallel and equal in length.
As all opposite sides are parallel in parallelogram,

Note: Before solving these types of questions, we need to be sure to have the knowledge about all the quadrilaterals and their basic properties. And it is equally important to go through all the options given. Otherwise, in a hurry, we may say only parallelogram or only rhombus as the answer. But this needs to be taken care of.