Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Context: The authors describe a family with six patients with muscular dystrophy with a variable course. One is a compound heterozygote for CAPN3 mutations (calpainopathy) and the others have a single CAPN3 mutation. Linkage analysis and sequencing revealed a XK gene mutation (McLeod syndrome). This illustrates the variable phenotype of XK mutations and suggests the possibility that CAPN3 heterozygotes may have their condition caused by nonallelic mutations in other unrelated genes. 
 Question: Mutation of which gene is associated with McLeod syndrome?
xk

Context: Billionaire Boy is a children's fiction book published on 28 October 2010 by HarperCollins and written by David Walliams and illustrated by Tony Ross. 
 Question: Who was Billionaire Boy illustrated by?
tony ross

Context: To develop clinical rules for the safe and effective use of flumazenil in suspected benzodiazepine overdose. We assembled a retrospective series of 35 consecutive comatose patients admitted between October 1992 and July 1993 to a toxicologic ICU with the presumptive diagnosis of drug overdose. These patients were divided into two groups. Group A (low-risk) patients had a clinical picture compatible with uncomplicated benzodiazepine intoxication (calm, without abnormalities in pulse or blood pressure, lateralizing signs, hypertonia, hyperreflexia, or myoclonus) in the absence of predefined electrocardiographic or clinical signs of tricyclic antidepressant or other proconvulsant overdose, and absence of an available history of long-term benzodiazepine treatment or an underlying seizure disorder. Group B ("non-low risk") comprised all other patients. Efficacy of flumazenil was categorized as complete awakening (with normal level of alertness), partial awakening, or no change in alertness level. The safety of flumazenil was defined on the basis of the absence of seizures or death. In group A (n=4), flumazenil was associated with complete awakening in three patients and partial awakening in one. No seizures were observed. In group B (n=31), flumazenil was associated with complete awakening in 4 patients, partial awakening in 5, and no response in 22. In group B, five seizures occurred. Comatose patients with clinical or ECG criteria thought to contraindicate the use of flumazenil have a reasonably high risk of seizures after administration of this drug. Low-risk patients may be able to receive flumazenil safely, but they may be only a small portion of comatose patients with suspected overdose. 
 Question: Which drug should be used as an antidote in benzodiazepine overdose?

flumazenil