**Core Concept**
Temozolomide is an oral chemotherapeutic agent used in the treatment of malignant gliomas. It acts by alkylating DNA, leading to DNA damage and subsequently inducing cell death. This process involves the formation of methylated lesions in DNA.

**Why the Correct Answer is Right**
Temozolomide works by undergoing spontaneous hydrolysis to form a methylating intermediate, which then methylates guanine residues in the DNA. This results in the formation of O-6-methylguanine (O6-MG), O-4-methylthymine (O4-MT), and N-7-methylguanine (N7-MG) adducts. The O6-MG adduct is particularly cytotoxic, as it can lead to the formation of DNA mismatches and mutations during DNA replication. Additionally, the O6-MG adduct can inhibit DNA repair enzymes, further contributing to the cytotoxic effects of temozolomide.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the mechanism of action of temozolomide.
**Option B:** This option is incorrect as it is not related to the mechanism of action of temozolomide.
**Option C:** This option is incorrect as it is not related to the mechanism of action of temozolomide.

**Clinical Pearl / High-Yield Fact**
Temozolomide's mechanism of action highlights the importance of DNA repair mechanisms in cancer treatment. Understanding the role of DNA repair enzymes in cancer cells can inform the development of targeted therapies.

**Correct Answer:** D.