Answer:
The correct answer is option A, which is a clock. Let's analyze why the clock is the correct answer.

Hands that cannot be held:
- When we think of "hands," we usually refer to the parts of our body that allow us to hold and manipulate objects. However, in this context, the term "hands" refers to the moving parts of a clock.
- The hands of a clock are the short and long pointers that indicate the time. They are called "hands" because they resemble human hands, but they cannot be physically held or grasped.

Explanation of the options:
a) Clock: A clock has two hands that move to indicate the time. These hands cannot be held or grasped by anyone.
b) Chair: A chair is a piece of furniture that is used for sitting. It does not have hands, so it cannot be the correct answer.
c) Spectacles: Spectacles, also known as glasses, are used to correct vision. They do not have hands, so they cannot be the correct answer.
d) Boy: A boy is a human being and has hands. Therefore, a boy does not fit the description of having two hands but not being able to hold them.

Conclusion:
Based on the given options, the only object that has two hands but cannot hold them is a clock. The hands of a clock are its moving parts that indicate the time, and they cannot be physically held or grasped.