In the following question, out of the four alternatives, select the one-word substitute that best expresses the given phrase: Study of tumors.

Introduction / Context:
This one word substitution question tests your knowledge of specialised scientific terms derived from Greek or Latin. The medical study of tumors is an important branch of medicine, and the correct term is used widely in hospitals, research and health related discussions.

Given Data / Assumptions:

• Phrase: Study of tumors.
• Options: Oenology, Oncology, Phrenology, Upology.
• We must pick the term that correctly names this medical specialty.
• We assume the common medical meanings of these suffixes: -logy referring to “study of”.

Concept / Approach:
Oncology is the branch of medicine dealing with tumors and cancers: their origin, development, diagnosis and treatment. Oenology is the study of wines and winemaking. Phrenology is a now discredited theory linking skull shape to mental abilities. “Upology” is not a recognised scientific term. Therefore, the only correct one word substitute for “study of tumors” is oncology.

Step-by-Step Solution:
Recognise that “study of” indicates a field ending typically in -logy.Recall the meaning of oncology: the medical science that studies tumors and cancers.Oenology (or enology) is related to wine, not to diseases.Phrenology deals with skull bumps and personality, not tumors.“Upology” is not a standard term in English; it appears meaningless here.Hence, oncology is the correct match.

Verification / Alternative check:
Think of common phrases: oncology department, oncologist, oncology ward. These all relate to cancer and tumor treatment in hospitals. There are no “tumor departments” called oenology or phrenology. When doctors specialise in cancer treatment, they are called oncologists, which strongly confirms that oncology is the study of tumors.

Why Other Options Are Wrong:
Oenology comes from Greek oinos for wine and refers to the study and science of wine and winemaking. Phrenology was a pseudo scientific theory dealing with reading character from the external shape of the skull; it has nothing to do with modern medical study of tumors. “Upology” is not a valid word in standard scientific vocabulary and seems to be included only as a distractor.

Common Pitfalls:
Students sometimes confuse technical sounding words simply because they all end in -logy. A good strategy is to build small groups: cardiology (heart), neurology (nerves), dermatology (skin), oncology (tumors and cancer). Remember that oenology relates to wine (often spelt enology in American English), and phrenology is more historical curiosity than real science. This makes oncology the only sensible choice here.

Final Answer:
The one word substitute for “study of tumors” is Oncology.