Which of these can be used for the fastest distribution of some injectible material/medicine and without risk of any kind?

The correct option is D

Veins

The correct option is D.

Explanation of the correct option:

1. The fastest mode of injection is intravenous.
2. An intravenous (IV) injection is an injection of a medication or another substance into a vein and directly into the bloodstream.

Explanation of the incorrect options:

Option A:

1. Intramuscular injection is the injection of a substance into a muscle.
2. This mode of injection is slower than intravenous injection.

Option B:

1. Intra-arterial injections are administered in chemotherapy.
2. These injections are used in brain tumors.

Option C:

1. Lymph vessels have a role in subcutaneous drug delivery.

Final answer: The fastest mode of injection or medicine delivery is through veins.